JP2006159644A - Inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer which can smoothly and stably pass recording papers. <P>SOLUTION: The inkjet printer transfers a paper 21a supplied from a paper feeding section 20 to an image recording section 40 having print heads 41 by a platen section 30 and prints by the print heads 41 and is provided with mask plates 11 having a paper guide section arranged near the print heads 41, guiding the paper 21a transferred by the platen section 30 to a space between the print heads 41 and the platen belt 31 of the platen section 30. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet printer having an ink jet print head.

  Conventionally, a printer has an inkjet print head, and ink droplets are ejected from a plurality of nozzles of these print heads onto a sheet transported by a sheet transport unit having a sheet suction function, thereby achieving high speed and high speed. 2. Related Art Inkjet printers that record high quality images are known.

  By the way, the environment in which such an ink jet printer is used is various, and is not limited to a room such as an office, but may be used in a poor environment. In particular, when used in a high temperature and high humidity environment, if the paper is left standing for a long time, the paper may absorb the surrounding water, and the edge of the cut sheet-like paper may be deformed into a curled shape. .

  When the curled paper is supplied and reaches the print head section, the curled portion of the paper may interfere with the nozzle surface of the print head, and the recording surface of the paper may be soiled. Arise. In addition, the curled portion of the paper may directly collide with the side surface of the print head, etc., and not only the paper conveyance becomes smooth, but also paper jam may occur, and the paper feeding may become unstable. . Further, when a relatively thick paper is supplied, the end of the paper hits the print head, which may damage the print head itself.

  Therefore, conventionally, in order to smoothly feed the curled paper, a curling suppression roller is prepared, and the curled portion of the paper is directly pressed by this roller. However, when such a roller is used, it is difficult to prevent ink, paper dust, dust, etc. from adhering to the roller, and therefore, ink, paper dust, dust, etc. adhering to the roller also adhere to the paper surface. There is also a problem that the image quality of the recorded image is remarkably deteriorated.

  Also, a method of suppressing the curled portion of the paper by strengthening the paper suction force used for the paper conveying means has been considered. However, strengthening the paper suction force causes the flow of ink mist ejected together with ink droplets from the print head to be noticeably generated near the edge of the paper, leading to paper smearing and again the quality of the recorded image. There was a problem of deterioration.

  In order to deal with such a problem, for example, as disclosed in Japanese Patent Application Laid-Open No. H10-228707, a sheet pressing unit having a pressing arm that suppresses lifting of the sheet in the vicinity of the print head has been proposed. According to this proposal, the floating of the sheet can be reliably suppressed immediately before the recording operation by the print head is performed.

Further, as disclosed in Patent Document 2, the nozzle face of the print head is arranged to be inclined with respect to the paper so that the gap between the nozzle face of the print head and the paper is increased in the paper transport direction. Proposals have also been proposed. According to this proposal, it is possible to prevent the deterioration of the image quality due to the cockling of the paper and realize high-speed printing.
JP 2001-26154 A JP-A-9-156087

  However, although the thing of patent document 1 can suppress the sheet | seat floating immediately before recording operation by a print head is performed, in the case of the sheet | seat with which the edge part curled, a curl part is just under a print head position. If the curl portion cannot be continuously suppressed and the curled portion comes directly under the print head, the end of the paper touches the nozzle surface of the print head, causing a problem that the image quality of the recorded image is deteriorated. In addition, if the curled portion of the paper rubs against the nozzle surface of the print head, paper dust on the paper may adhere to the nozzle portion of the print head, which may cause ink non-ejection and the like. This causes the problem of deterioration.

  Further, in Patent Document 2, since the gap between the nozzle surface of the print head and the paper is increased in the paper conveyance direction, interference of the curled portion of the paper immediately below the print head can be avoided. it can. However, it is unavoidable that the curled portion of the paper collides with the side surface of the print head or the like, and not only the movement of the paper becomes smooth, but also the paper passing may become unstable such as the paper jamming. Further, when a relatively thick paper is supplied, the end of the paper hits the print head, which may damage the print head itself.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an ink jet printer capable of smoothly and stably passing paper.

  According to a first aspect of the present invention, there is provided a sheet feeding unit for supplying a recording sheet, a sheet conveying unit for conveying the recording sheet supplied from the sheet feeding unit, and the recording sheet conveyed by the sheet conveying unit. A print head having a nozzle for ejecting ink droplets for printing, and the recording paper that is disposed in the vicinity of the print head and is conveyed by the paper conveyance means is placed in a space between the print head and the paper conveyance means. The paper guide means for guiding is provided.

  According to a second aspect of the present invention, in the first aspect of the present invention, the paper guide means has a base end, and a space between the print head and the paper transport means extends from the base end in the paper transport direction. And a paper guide part having a projecting part projecting toward the paper transporting means, and a protrusion of the paper guide part. A gap between the print head and the paper conveying means is made narrower than a gap between the print head and the paper conveying means, and the protruding portion is located upstream of the nozzle in the paper conveying direction. It is characterized by the arrangement.

  According to a third aspect of the present invention, in the second aspect of the present invention, the paper guide means is characterized in that the base end portion is supported by a support member arranged side by side with the print head.

  According to a fourth aspect of the present invention, in the second aspect of the present invention, the paper guide means is fixed to the print head.

  According to a fifth aspect of the present invention, in the invention according to any one of the second to fourth aspects, the paper guide means has a facing surface facing the print head, and ink droplets from the nozzles are placed on the facing surface. It is characterized in that an opening that passes therethrough is formed.

  According to a sixth aspect of the present invention, in the first aspect of the invention, the paper guide means is disposed on the upstream side in the paper conveyance direction in the vicinity of the print head, and is provided with respect to the corner portion and the paper conveyance means. An inclined portion having a predetermined angle, and the print head is arranged to be inclined so that a gap with the sheet conveying unit becomes wider toward a downstream side in the sheet conveying direction, and a corner portion of the sheet guide unit The gap between the sheet conveying unit and the sheet conveying unit is narrower than the gap between the upstream end of the print head in the sheet conveying direction and the sheet conveying unit.

  According to a seventh aspect of the invention, in the first aspect of the invention, the paper guide means is disposed on the upstream side in the paper conveyance direction in the vicinity of the print head and has a base end portion. An inclined portion formed by bending a predetermined angle on the upstream side in the paper conveyance direction and on the paper conveyance means side, the bent portion is formed in a corner portion, and a gap between the corner portion and the paper conveyance means is It is characterized in that it is narrower than the gap between the print head and the paper conveying means.

  According to an eighth aspect of the present invention, in the first aspect of the present invention, the paper guide means is disposed on the upstream side in the paper transport direction in the vicinity of the print head, and has a base end portion. An inclined portion formed by bending a tip at a predetermined angle on the downstream side in the paper conveying direction and on the paper conveying means side, and a regulating portion formed by bending the tip of the inclined portion in the horizontal direction, The gap between the printing head and the sheet conveying means is narrower than the gap between the print head and the sheet conveying means.

  According to a ninth aspect of the invention, in the first aspect of the invention, the print head is widened at least at the downstream end in the paper transport direction as the gap with the paper transport means goes downstream in the paper transport direction. Such an inclined part is formed.

  According to a tenth aspect of the present invention, in the first aspect of the invention, the print head is a line head fixed to the recording paper.

  ADVANTAGE OF THE INVENTION According to this invention, the inkjet printer which can pass a paper smoothly and stably can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows a schematic configuration of an ink jet printer according to a first embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes a printer main body. The printer main body 1 includes a paper feed unit 20 as a paper feed unit, a platen unit 30 as a paper transport unit, an image recording unit 40 having a print head, and a discharge unit 50. Has been. In the figure, an axis in the conveyance direction of a sheet 21a, which will be described later, is a Y axis, and an axis in a direction perpendicular to the Y axis is an X axis in the plane of the sheet 21a moved along the Y axis. The vertical axis perpendicular to the Y axis is taken as the Z axis.

  The paper supply unit 20 includes a paper tray 21 as a paper storage unit, a pickup roller 22 as a paper take-out unit, and a registration roller pair 23 as a conveyance direction adjusting unit.

  The paper tray 21 stores at least one paper 21a that is a recording paper. In this embodiment, a large number of cut sheet-like sheets 21 a are stacked in the sheet tray 21. The pickup roller 22 is rotatably supported by a frame (not shown) of the printer main body 1, and by the rotation, the paper 21 a in the paper tray 21 is separated and taken out one by one and fed into the printer main body 1. I am doing so. The registration roller pair 23 is rotatably supported by a frame (not shown) of the printer main body 1, and is aligned with the conveyance direction in order to adjust the printing timing of the paper 21 a taken out by the pickup roller 22. The aligned paper 21 a is conveyed to the platen unit 30.

  The platen unit 30 conveys the paper 21 a sent from the paper feeding unit 20 to the image recording unit 40. The platen unit 30 includes a platen belt 31, a plurality of platen belt rollers 32, a platen frame 33, and a platen suction unit 34 as negative pressure generating means. The platen belt 31 is composed of an endless belt, suspended on a plurality of platen belt rollers 32 attached to the platen frame 33, and cooperates to transfer the paper 21a in the Y-axis direction. In this case, the platen belt 31 and the platen belt roller 32 are configured to move the platen belt 31 in a platen paper conveyance region 31b facing the image recording unit 40, and set the conveyance direction of the paper 21a with respect to the image recording unit 40. is doing.

  FIG. 2 is a diagram for further explaining the platen unit 30, and here, the platen belt 31 is shown only about half in the Y-axis direction. In this case, the platen belt 31 is provided with a large number of suction holes 31a as a whole. In addition, the plurality of platen belt rollers 32 have both side edges of the platen belt 31 parallel to the Y axis and the width direction in the platen paper conveyance region 31b (see FIG. 1) where the platen belt 31 and the image recording unit 40 face each other. The platen belt 31 is supported so as to be parallel to the X axis.

  The platen belt roller 32 is connected to at least one of the rotation shafts of the roller drive motor 32a so that the platen belt roller 32 can be driven to rotate. Although not shown here, a driven roller is disposed at a position facing the platen belt roller 32 in the Z-axis direction so as to prevent the sheet 21a placed on the platen belt 31 from being lifted.

  A platen frame 33 is disposed below the platen belt 31. The platen frame 33 has a plane 33a along the X axis and the Y axis, and supports the platen belt 31 on the plane 33a. A plurality of grooves 33 d that are elongated in the Y-axis direction are formed on the flat surface 33 a of the platen frame 33 over the entire region facing the platen belt 31. A suction hole 33e penetrating a platen chamber, which will be described later, is provided in a substantially central portion of the grooves 33d. The platen frame 33 supports the platen belt roller 32 in a rotatable manner and holds a platen suction part 34.

  Returning to FIG. 1, the platen suction portion 34 generates a negative pressure for adsorbing the paper 21 a on the platen belt 31 and is attached to the platen frame 33. The platen suction part 34 is provided with a platen chamber (not shown). This platen chamber has a negative pressure generating source for making a negative pressure in its own chamber. As this negative pressure generating source, known negative pressure generating means such as a fan is used. As a result, the platen suction section 34 sucks air from the suction holes 33e of the platen frame 33 due to the negative pressure of the negative pressure generation source of the platen chamber, and the paper being conveyed through the numerous suction holes 31a of the platen belt 31. 21a is sucked.

  The image recording unit 40 constitutes an ink ejection device that ejects ink for printing onto the paper 21 a conveyed by the platen belt 31. The image recording unit 40 includes a plurality of print heads 41 and a carriage 42.

  The print head 41 is composed of an aggregate of image recording heads for recording images. The print head 41 has a width that is equal to or greater than the maximum width of the paper to be used. For example, when the paper used is A3, one having a width dimension equal to or larger than the width dimension of the paper is used. Further, the print head 41 constitutes a fixed line head that is fixed to the paper 21 a conveyed by the platen belt 31.

  Further, the print heads 41 are provided for the number of colors. Here, a total of four print heads 41 of black (K), cyan (C), magenta (M), and yellow (Y) are used. In the drawings, the reference numerals indicating the print heads 41 are indicated by subscripts (K, C, M, Y) representing the respective colors. These print heads 41 are supported by a carriage 42.

  A mask plate 11 serving as a sheet guide means is disposed in the vicinity of the print head 41 of the image recording unit 40.

  FIG. 3 shows an enlarged view of the vicinity of the print head 41 on which such a mask plate 11 is arranged. In this case, the carriage 42 is provided with a rib 42 a as a support member alongside the print head 41. The rib 42a is provided so as to protrude toward the platen belt 31, and the mask plate 11 is provided at the tip. For this mask plate 11, for example, a SUS plate material of about 0.2 mm, which has been subjected to a surface treatment for reducing the friction coefficient, is used.

  The mask plate 11 has a base end portion 11c fixed to the tip of the rib 42a, and extends from the base end portion 11c to the upstream side in the paper transport direction via a space between the print head 41 and the platen belt 31. At the same time, a print head side facing surface 11b that is inclined at a predetermined angle toward the lower side (platen belt 31 side) is formed, and an upper portion of the print head side facing surface 11b by a predetermined angle (opposite to the platen belt 31). The paper guide portion 11a is formed by folding the sheet guide portion 11a. Here, the paper guide portion 11 a is for guiding the leading end portion of the paper 21 a conveyed by the platen portion 30 to the space between the print head 41 and the platen belt 31. The print head side facing surface 11b is located at a position facing the front end of the print head 41 so as to gradually widen the space with the platen belt 31 in the conveyance direction of the paper 21a. The print head side facing surface 11 b faces the print head 41 so that ink droplets 41 c ejected from the nozzles 41 b formed on the nozzle plate 41 a of the print head 41 can land on the paper 21 a on the platen belt 31. An opening portion 11d through which the ink droplet 41c passes is formed on the surface to be performed.

  The mask plate 11 is disposed such that the bent portion A protruding to the platen belt 31 side of the paper guide portion 11a is closest to the platen belt 31, and the gap G1 between the bent portion A and the platen belt 31 is set to the print head. The gap G2 between the nozzle plate 41a of the 41 and the platen belt 31 is made sufficiently narrower. Further, the bent portion A is located upstream of the nozzle 41 b formed on the nozzle plate 41 a of the print head 41 in the paper transport direction.

  Returning to FIG. 1, the discharge unit 50 is a mechanism for discharging the paper 21 a on which an image is recorded by the image recording unit 40, and includes a discharge unit transport roller pair 51, a discharge unit discharge roller pair 52, and a discharge tray 53. Yes. The discharge unit conveyance roller pair 51 is for conveying the paper 21 a conveyed from the platen unit 30 into the discharge unit 50. The discharge unit discharge roller pair 52 is for discharging the paper 21 a conveyed from the discharge unit conveyance roller pair 51 to the discharge tray 53.

  Next, the operation of the embodiment configured as described above will be described.

  In this case, the cut sheet-like sheets 21 a stacked in the sheet tray 21 of the sheet feeding unit 20 are separated and taken out one by one by the pickup roller 22. Then, after the printing timing is adjusted by the registration roller pair 23, it is supplied onto the platen belt 31 of the platen unit 30. The sheet 21 a supplied to the platen belt 31 is sucked and held on the platen belt 31 by the platen suction unit 34, and further conveyed by driving the platen belt roller 32, and the print head 41 (K) for each color of the image recording unit 40. , 41 (C), 41 (M), and 41 (Y), the recording of each color image is performed. Then, the sheet 21 a on which the image is recorded by the image recording unit 40 is conveyed into the discharge unit 50 by the discharge unit conveyance roller pair 51, and is discharged to the discharge tray 53 through the discharge unit discharge roller pair 52.

  Next, the case where the curled paper 21a at the leading end is supplied from the paper tray 21 will be described.

  In this case, when the paper 21 a is supplied from the paper supply unit 20 to the platen unit 30, the paper 21 a is attracted to the platen belt 31 and conveyed. When reaching the mask plate 11, the curled portion of the paper 21 a advances while rubbing the inclined surface of the paper guide portion 11 a and is guided to the gap G 1 between the bent portion A and the platen belt 31. Then, after passing through the gap G1, the sheet 21a surface is guided to the space between the print head side facing surface 11b and the platen belt 31 while the conveyance direction is restricted by the sheet 21a being in contact with the bent portion A.

  In this case, the curling portion of the paper 21a is regulated by the bent portion A positioned upstream in the paper transport direction with respect to the nozzle 41b of the paper guide portion 11a, so that the curled portion is the print head side facing surface. It is conveyed without touching 11b. Even if the curled portion of the paper 21a rubs against the print head side facing surface 11b, the curled portion of the paper 21a does not directly touch the nozzle plate 41a of the print head 41 due to the presence of the print head side facing surface 11b. Further, since a space is formed between the print head side facing surface 11b and the nozzle plate 41a of the print head 41 by the mask plate 11, the mist of the ink droplet 41c discharged from the nozzle 41b is opposed to the print head side. It only adheres to the surface of the surface 11b on the print head 41 side, and does not adhere to the platen belt 31 side. Thereby, even if the curled portion of the paper 21a touches the print head side facing surface 11b, the ink is not stained.

  Accordingly, when the sheet 21a is supplied from the sheet feeding unit 20 to the platen unit 30, the leading end of the sheet 21a is smoothly guided to the gap G1 by the function of the sheet guide unit 11a of the mask plate 11. Therefore, even if the paper 21a with the curled tip is conveyed, the paper 21a can be moved smoothly and jamming can be reliably prevented. Further, when the paper 21a passes through the gap G1, the conveyance height is regulated by the bent portion A of the paper guide portion 11a, and the paper 21a is guided to the space between the print head side facing surface 11b and the platen belt 31. Even if the paper 21a does not touch the print head side facing surface 11b, even if the print head side facing surface 11b is rubbed, the presence of the print head side facing surface 11b causes the curl of the paper 21a on the nozzle plate 41a of the print head 41. The part can be prevented from touching.

  As a result, it is possible to prevent deterioration in image quality caused by dirt on the printing surface or non-ejection of ink caused by the paper 21a rubbing against the nozzle surface of the print head 41. Further, since the paper 21a can be moved smoothly, paper jams are reduced, there is no possibility of damage to the print head 41, and even if the paper 21a has a curled tip, stable paper feeding can be performed.

  Further, since the mask plate 11 is made of a thin SUS material having elasticity, it is elastically held on the rib 42a of the carriage 42. Thereby, for example, even when the thick paper 21a is transported and the leading edge of the paper 21a collides with the paper guide portion 11a of the mask plate 11, the mask plate 11 is elastically deformed, which causes an obstacle to the transport of the paper 21a. The frequency of occurrence of paper jam can be further reduced.

Further, since the nozzle plate 41a of the print head 41 is parallel to the platen belt 31 and the ink droplet 41c is landed perpendicularly to the paper 21a, the ink droplet 41c is landed vertically on the paper 21a. The flight distance can be shortened, and even if the paper 21a floats or the thickness varies, the deviation of the landing position can be reduced.

In the present embodiment, the rib 42a is disposed downstream of the print head 41 in the sheet conveyance direction. However, the rib 42a is disposed upstream of the print head 41, and the paper guide portion 11a is disposed on the rib 42a. You may make it fix to.

(Modification)
Next, a modification of the first embodiment will be described.

  FIG. 4 shows a schematic configuration of a main part (near the print head) of a modification of the first embodiment, and the same reference numerals are given to the same parts as those in FIG. In this case, the mask plate 12 has a base end portion 12 c and the base end portion 12 c is directly attached to the side surface of the print head 41. The mask plate 12 also extends from the base end portion 12c to the upstream side in the paper conveyance direction via a space between the print head 41 and the platen belt 31, and is also directed downward (to the platen belt 31 side). The print head side facing surface 12b is formed by inclining at an angle, and the leading end portion of the print head side facing surface 12b is bent upward (on the side opposite to the platen belt 31) by a predetermined angle to form the paper guide portion 12a. . Also here, the paper guide portion 12 a is for guiding the leading end portion of the paper 21 a conveyed by the platen portion 30 to the space between the print head 41 and the platen belt 31. The print head side facing surface 12b is located at a position facing the front end of the print head 41 so as to gradually widen the space with the platen belt 31 in the conveyance direction of the paper 21a. The print head side facing surface 12b faces the print head 41 so that the ink droplets 41c ejected from the nozzles 41b formed on the nozzle plate 41a of the print head 41 can land on the paper 21a on the platen belt 31. An opening 12d is formed on the surface to be performed.

  The mask plate 12 is arranged so that the bent portion A of the paper guide portion 12a is closest to the platen belt 31, and the gap G11 between the bent portion A and the platen belt 31 is set to the nozzle plate 41a of the print head 41 and the platen belt. The gap G12 between the belt 31 and the belt 31 is sufficiently narrower. The print head side facing surface 12b faces the print head 41 so that the ink droplets 41c ejected from the nozzles 41b formed on the nozzle plate 41a of the print head 41 can land on the paper 21a on the platen belt 31. An opening 12d is formed on the surface to be performed.

  Even when the mask plate 12 configured as described above is used, when the sheet 21a with the curled tip is supplied, the same operation as the mask plate 11 described in the first embodiment can be obtained.

  Accordingly, in this way, in addition to the effect of using the mask plate 11 described in the first embodiment, the mask plate 12 is further directly attached to the print head 41 and integrated. This is effective in saving the surrounding space, and the entire apparatus can be downsized.

  In this modification, the mask plate 12 is fixed to the side surface on the downstream side in the paper conveyance direction with respect to the print head 41. However, avoid the nozzle 41b on the side surface on the upstream side of the print head 41 or on the surface of the nozzle plate 41a. It may be fixed.

  Further, the mask plates 11 and 12 used in the above-described embodiment are formed by integrally forming the paper guide portion 11a (12a) and the print head side facing surface 11b (12b). Even with this configuration, as described above, there can be obtained an ink jet printer that does not deteriorate the recorded image, has little paper jam, does not cause damage to the print head, and can pass the paper even on the curled paper stably. .

(Second Embodiment)
Next, a second embodiment of the present invention will be described.

  FIG. 5 shows a schematic configuration of a main part (in the vicinity of the print head) of the second embodiment of the present invention. The same reference numerals are given to the same parts as those in FIG. In the drawing, 13 is a paper guide, and this paper guide 13 is arranged in the vicinity of the print head 41 in the upstream side in the paper transport direction. The paper guide 13 extends the tip of a base end portion 13c fixed to a vertical surface of a rib (not shown) to the upstream side in the paper transport direction and is substantially perpendicular to the base end portion 13c (a direction along the platen belt 31). The corner portion 13b is formed, and the tip portion of the corner portion 13b is bent upward (on the opposite side to the platen belt 31) by a predetermined angle to form the inclined portion 13a. Here, the inclined portion 13 a is for guiding the leading end of the paper 21 a conveyed by the platen unit 30 to the space between the print head 41 and the platen belt 31.

  On the other hand, the print head 41 is disposed so as to be inclined so that the gap between the nozzle plate 41 a having a plurality of nozzles 41 b and the platen belt 31 becomes wider toward the downstream in the paper transport direction.

  In this state, the paper guide 13 is disposed such that the corner portion 13b is closest to the platen belt 31, and the gap G21 between the corner portion 13b and the platen belt 31 is inclined to form the paper on the nozzle plate 41a of the print head 41. The gap G22 between the upstream end in the transport direction and the platen belt 31 is made narrower.

  Even when the paper guide 13 configured as described above and the print head 41 disposed at an inclination are used, when the paper 21a with the curled tip is supplied, it is the same as the mask plate 11 described in the first embodiment. Operation can be obtained.

  Accordingly, in this case, the paper guide 13 having the inclined portion 13a and the corner portion 13b is provided on the upstream side in the paper conveyance direction in the vicinity of the print head 41 arranged at an inclination, and the gap between the corner portion 13b and the platen belt 31 is provided. Since G21 is configured to be narrower than the gap G22 between the upstream end portion of the nozzle plate 41a of the print head 41 in the paper transport direction and the platen belt 31, the curled paper 21a at the front end portion is supplied. In addition, it is possible to reliably prevent the leading edge of the paper 21a from coming into contact with the side surface on the upstream side of the print head 41, and the same effect as in the first embodiment can be obtained.

In addition, since no other member is used to form a gap between the nozzle plate 41a of the print head 41 and the platen belt 31, the gap G22 can be narrowed, and the recorded image can be improved in image quality. Is also effective.

  In the present embodiment, the paper guide 13 is formed by bending a thin SUS plate material. However, the inclined portion 13a may be chamfered on the block.

(Third embodiment)
Next, a third embodiment of the present invention will be described.

  FIG. 6 shows a schematic configuration of the main part (in the vicinity of the print head) of the third embodiment of the present invention. The same parts as those in FIG. In the drawing, 14 is a paper guide, and this paper guide 14 is arranged in the vicinity of the print head 44 in the upstream side in the paper transport direction. The paper guide 14 bends the tip of a base end portion 14c fixed to a vertical surface of a rib (not shown) upward a predetermined angle (on the opposite side to the platen belt 31) on the upstream side in the paper transport direction to form an inclined portion 14a. The bent portion is formed in the corner portion 14b. Here, the inclined portion 14 a is for guiding the leading end of the paper 21 a conveyed by the platen unit 30 to the space between the print head 44 and the platen belt 31.

  On the other hand, the print head 44 has an inclined portion 44c formed at the downstream end in the paper transport direction. The inclined portion 44c is formed so that the gap with the platen belt 31 becomes wider as it goes downstream in the paper conveyance direction. Accordingly, the downstream side in the paper conveyance direction of the nozzle plate 44a having the plurality of nozzles 44b is formed. It is shaped to be cut.

  In this state, the paper guide 14 is disposed so that the corner portion 14b is closest to the platen belt 31, and a gap G31 between the corner portion 14b and the platen belt 31 is set between the nozzle plate 44a of the print head 44 and the platen belt 31. It is made narrower than the gap G32.

  Even when the print head 44 with the inclined portion 44c formed at the downstream end in the paper conveyance direction is used together with the paper guide 14 configured as described above, when the paper 21a with the curled tip is supplied, A similar operation described in the first embodiment can be obtained.

  Therefore, in this way, the paper guide 14 having the inclined portion 44c formed at the downstream end in the paper conveyance direction and the inclined portion 14a and the corner portion 14b formed on the upstream side in the paper conveyance direction near the print head 44 is provided. Since the gap G31 between the corner portion 14b and the platen belt 31 is narrower than the gap G32 between the nozzle plate 44a and the platen belt 31 of the print head 44, the curled paper 21a at the leading end is supplied. Even in this case, it is possible to reliably prevent the leading edge of the paper 21a from interfering with the print head 44, and the same effects as those of the first embodiment can be obtained.

  Further, since no other member is used to form a gap between the nozzle plate 44a of the print head 44 and the platen belt 31, the gap G32 can be narrowed. Further, the nozzle plate 44a of the print head 44 is provided with the platen belt 31. , The gap G32 between them can be further narrowed, the landing of the ink droplets on the paper 21a and the reduction of mist can be obtained, and further higher image quality can be realized. .

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.

  FIG. 7 shows a schematic configuration of a main part (in the vicinity of the print head) of the fourth embodiment, and the same reference numerals are given to the same parts as those in FIG. In the figure, reference numeral 15 denotes a paper guide, and this paper guide 15 is arranged on the upstream side in the paper transport direction in the vicinity of the print head 45. The paper guide 15 bends the tip of a base end portion 15c fixed to a vertical surface of a rib (not shown) to the downstream side in the paper transport direction by a predetermined angle downward (opposite the platen belt 31) to form an inclined portion 15a. Further, the tip of the inclined portion 15a is bent in the horizontal direction to form the restricting portion 15b. Here, the inclined portion 15 a is for guiding the leading end of the paper 21 a conveyed by the platen unit 30 to the space between the print head 45 and the platen belt 31.

  On the other hand, in the print head 45, an inclined portion 45c is formed at the downstream end in the paper transport direction, and an inclined portion 45d is formed at the upstream end. The inclined portion 45c is formed such that the gap with the platen belt 31 becomes wider as it goes downstream in the paper conveyance direction, and the inclined portion 45d becomes wider as the gap with the platen belt 31 goes upstream in the paper conveyance direction. As a result, the upstream and downstream sides of the nozzle plate 45a having the plurality of nozzles 45b in the paper transport direction are scraped.

  In this state, the paper guide 15 is disposed so that the restricting portion 15b is closest to the platen belt 31, and a gap G41 between the restricting portion 15b and the platen belt 31 is set between the nozzle plate 45a of the print head 45 and the platen belt 31. The gap G42 is made narrower.

  Along with the paper guide 15 configured in this manner, inclined portions 45c and 45d are formed at the upstream and downstream ends of the paper conveyance direction, and even when the print head 45 is used, the curled paper 21a at the leading edge is supplied. The same operation as described in the first embodiment can be obtained.

  Accordingly, in this case, the inclined portions 45c and 45d are formed at the upstream and downstream ends of the paper conveyance direction, and the inclined portion 15a and the regulation portion 15b are formed on the upstream side in the paper conveyance direction near the print head 45. Since the guide 15 is provided and the gap G41 between the restricting portion 15b and the platen belt 31 is configured to be narrower than the gap G42 between the nozzle plate 45a of the print head 45 and the platen belt 31, the paper with the curled end portion Even when 21a is supplied, it is possible to reliably prevent the leading edge of the paper 21a from interfering with the print head 45, and the same effects as those of the first embodiment can be obtained.

  Further, since no other member is used to form a gap between the nozzle plate 45a of the print head 45 and the platen belt 31, the gap G41 can be narrowed. Further, the nozzle plate 45a of the print head 45 is provided with the platen belt 31. Since the gap G41 is further narrowed, the landing of the ink droplets on the paper 21a and the reduction of the mist can be obtained, and the image quality can be further improved. .

  Furthermore, since the inclined portions 45c and 45d formed at the upstream and downstream ends of the print head 45 in the paper conveyance direction are arranged symmetrically around the nozzle 45b, the direction is not considered when assembling the carriage. There is also an effect that it can be completed.

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not change the summary. For example, the paper guide portions 11a, 12a, 13, 14, and 15 used in the first to fourth embodiments described above are inclined planes, but may be smooth curved surfaces, If each of the bent portions A, corner portions 13b and 14b, and restricting portion 15b is changed from an acute shape to a curved surface, the paper 21a itself is not damaged.

  Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and is described in the column of the effect of the invention. If the above effect is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

1 is a diagram illustrating a schematic configuration of an ink jet printer according to a first embodiment of the present invention. The figure which shows schematic structure of the platen part used for 1st Embodiment. FIG. 3 is an enlarged view showing the vicinity of a print head of a main part of the first embodiment. The figure which expands and shows the print head vicinity of the principal part of the modification of 2nd Embodiment. The figure which expands and shows the print head vicinity of the principal part of the 2nd Embodiment of this invention. The figure which expands and shows the print head vicinity of the principal part of the 3rd Embodiment of this invention. The figure which expands and shows the print head vicinity of the principal part of the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printer main body, 11 ... Mask plate 11a ... Paper guide part, 11b ... Print head side opposing surface 11c ... Base end part, 11d ... Opening part 12 ... Mask plate, 12a ... Paper guide part 12b ... Print head side opposing surface, 12c: Base end portion 12d: Opening portion, 13 ... Paper guide, 13a ... Inclined portion 13b ... Corner portion, 13c ... Base end portion, 14 ... Paper guide 14a ... Inclined portion, 14b ... Corner portion 14c ... Base end portion, 15 ... Paper guide, 15a ... Inclined part 15b ... Regulator part, 15c ... Base end part, 20 ... Paper feeding part 21a ... Paper, 21 ... Paper tray, 22 ... Pickup roller 23 ... Registration roller pair, 30 ... Platen part 31 ... Platen belt, 31a ... Suction hole 31b ... Platen paper transport area, 32 ... Platen belt roller 32a ... Roller drive motor, 33 ... Platenf 33a ... Flat surface, 33d ... Groove, 33e ... Suction hole 34 ... Platen suction part, 40 ... Image recording part 41 ... Print head, 41a ... Nozzle plate 41b ... Nozzle, 41c ... Ink droplet, 42 ... Carriage 42a ... Rib, 44 ... print head, 44a ... nozzle plate 44b ... nozzle, 44c ... inclined portion 45 ... print head, 45a ... nozzle plate 45b ... nozzle, 45c ... inclined portion, 45d ... inclined portion 50 ... discharge portion, 51 ... discharge portion transport roller Pair 52 ... Discharge part discharge roller pair 53 ... Discharge tray

Claims (10)

Paper feeding means for supplying recording paper;
A paper conveying means for conveying the recording paper supplied from the paper feeding means;
A print head having nozzles for ejecting ink droplets for printing on the recording paper conveyed by the paper conveying means;
An ink jet comprising: paper guide means disposed in the vicinity of the print head and guiding the recording paper conveyed by the paper conveyance means to a space between the print head and the paper conveyance means. Printer. The paper guide means has a base end portion, extends from the base end portion in the paper transport direction through a space between the print head and the paper transport means, and is inclined at a predetermined angle in the paper transport direction. And a paper guide portion having a protruding portion protruding toward the paper conveying means side,
The gap between the protruding portion of the paper guide portion and the paper conveying means is made narrower than the gap between the print head and the paper conveying means, and the protruding portion is located on the paper with respect to the nozzle. 2. The ink jet printer according to claim 1, wherein the ink jet printer is arranged on an upstream side in a transport direction. 3. The ink jet printer according to claim 2, wherein the paper guide means has the base end portion supported by a support member arranged side by side with the print head. 3. The ink jet printer according to claim 2, wherein the paper guide means is fixed to the print head. 5. The sheet guide unit according to claim 2, wherein the sheet guide unit has a facing surface facing the print head, and an opening through which ink droplets from the nozzle pass is formed on the facing surface. Inkjet printer. The paper guide means is disposed on the upstream side in the paper conveyance direction in the vicinity of the print head, and includes a corner portion and an inclined portion having a predetermined angle with respect to the paper conveyance means,
The print head is arranged so as to be inclined so that a gap with the paper transport unit becomes wider toward the downstream in the paper transport direction,
The gap between the corner portion of the paper guide unit and the paper transport unit is narrower than the gap between the upstream end of the print head in the paper transport direction and the paper transport unit. The ink jet printer according to claim 1. The paper guide means is disposed on the upstream side in the paper transport direction in the vicinity of the print head, has a base end portion, and the base end portion is located at a predetermined angle on the upstream side in the paper transport direction and on the paper transport means side. An inclined part formed by bending, and forming the bent part in a corner part,
2. The ink jet printer according to claim 1, wherein a gap between the corner portion and the paper transport unit is narrower than a gap between the print head and the paper transport unit. The paper guide means is disposed on the upstream side in the paper transport direction in the vicinity of the print head, has a base end, and the tip of the base end is on the downstream side in the paper transport direction and on the paper transport means side. An inclined portion formed by bending at a predetermined angle, and a regulating portion formed by bending the tip of the inclined portion in the horizontal direction,
2. The ink jet printer according to claim 1, wherein a gap between the restricting portion and the paper transport unit is narrower than a gap between the print head and the paper transport unit. 2. The print head according to claim 1, wherein an inclined portion is formed at an end portion at least downstream in the paper transport direction so that a gap with the paper transport means becomes wider toward the downstream in the paper transport direction. The inkjet printer according to 1. 2. The ink jet printer according to claim 1, wherein the print head is a line head fixed to the recording paper.

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