JP3125442U - Printing device - Google Patents

Abstract

A printing apparatus that can reliably correct curl of printing paper and does not generate a defective print surface even in double-sided printing.
SOLUTION: A conveyance belt 3c that moves along a conveyance path, a conveyance device 3 that conveys printing paper P fed on the conveyance belt 3c in a conveyance direction, and conveyance of the conveyance device 3. The print head 4 is provided on the upper surface side of the path, and the curl correcting means 5 is disposed upstream of the print head 4 in the transport path and corrects the curl of the printing paper P. The curl correcting means 5 includes the transport belt. A pair of upper rolls 10 and 10 disposed on the upper surface side of 3c and spaced from each other in the sheet conveyance direction, and disposed on the lower surface side of the conveyance belt 3c and between the pair of upper rolls 10 and 10. From the non-correcting position where the moving direction of the conveying belt 3c is not bent and the lower roll 11 provided movably between the curl correcting position where the moving direction of the conveying belt 3c is bent convexly toward the upper roll 10 side. Configured
[Selection] Figure 2

Description

  The present invention relates to a printing apparatus provided with means for correcting curling of printing paper.

  A non-contact type print head (for example, an ink jet type) cannot perform proper printing unless the distance from the print paper is a predetermined distance. Therefore, the print paper is positioned at a predetermined distance from the print head. It is formed to convey.

  On the other hand, when an image is formed on a general printing paper, the fiber of the paper absorbs moisture in the water-based ink and swells, and curls due to this swelling. In addition, some printing papers on which no image is formed are curled. When the curled printing paper is used in a non-contact type printing head (for example, ink jet type) printing apparatus, proper printing cannot be performed. In addition, when the curl of the printing paper is large, there is a problem that the printing paper interferes with the print head. Therefore, in order to prevent such a problem, a printing apparatus including a curl correcting unit that corrects curling of printing paper has been proposed.

  As this type of conventional printing apparatus, for example, there is one disclosed in Patent Document 1. As shown in FIG. 4, the printing apparatus 100 includes an infinite end conveyor belt 101a that moves along a conveyance path, and conveys the printing paper P fed on the conveyor belt 101a in the sheet conveyance direction. A paper transport unit 101, a plurality of ink jet type print heads 102 disposed on the upper surface side of the transport path of the paper transport unit 101 and at a predetermined interval, and an upstream position from the most upstream print head 102 And a curl correcting means 104 for correcting the curl of the printing paper P.

  The sheet conveying unit 101 includes a conveying belt 101a, a plurality of driven pulleys 101b and a driving pulley 101c around which the conveying belt 101a is stretched, and a driving motor 101d that drives the driving pulley 101c.

  As shown in FIG. 5, the curl correcting means 104 is arranged on the upper side of the conveyance path, is soft and has a large-diameter upper roll 105, and is arranged on the lower side of the conveyance path, is hard, and has a small diameter. The lower roll 106 is configured. The upper roll 105 is spaced above the lower roll 106 and is brought into pressure contact with the lower roll 106 and the non-correcting position (dashed line position in FIG. 5) through which the printing paper P passes straight without being bent. It is provided so as to be movable between a curl correction position where the direction is bent upward and convex.

In the above configuration, as shown in FIG. 6, in the case of the printing paper P with the leading end curled upward, the upper roll 105 of the curl correcting means 104 is set as the curl correcting position. Then, when the printing paper P passes between the upper roll 105 and the lower roll 106 of the curl correcting means 104, the printing paper P is curled downward as indicated by a broken line in FIG. 6, thereby correcting the upward curling. Is done. Accordingly, the curled straightened printing paper P passes through a position separated from the print heads 102 and 103 by a predetermined distance, so that proper printing is performed.
Japanese Patent Laid-Open No. 2002-2005

  However, in the conventional printing apparatus 100, since the upper roll 105 is pressed against the lower roll 106 and the upper roll 105 is compressed and deformed along the lower roll 106, a convex curl correction path is formed. There is a problem that the degree of convexity is small and the curl correction force is small. Therefore, there is a possibility that the curl of the printing paper P cannot be reliably corrected.

  Further, since the printing paper P is conveyed while being pressed between the upper roll 105 and the lower roll 106 that are in pressure contact with each other, in the case of duplex printing, the ink adhesion surface immediately after printing strongly presses against the lower roll 106. Is done. For this reason, the lower roll 106 may cause damage such as ink bleeding and ink rubbing on the ink adhering surface, which may cause a defective printing surface.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a printing apparatus that can reliably correct curling of printing paper and that does not generate a defective print surface in the case of duplex printing. And

  The invention of claim 1 has a conveyance belt that moves along a conveyance path, a sheet conveyance means that conveys printing paper fed on the conveyance belt in the sheet conveyance direction, and a conveyance path of the sheet conveyance means A printing head provided on one side of the printing paper, and a curling correction means arranged at a position upstream of the printing path from the printing head to correct the curl of the printing paper. A pair of upper rolls arranged on one side and spaced in the paper conveyance direction, and arranged on the other side of the conveyance belt and between the pair of upper rolls, It is composed of a non-correcting position where the direction is not bent and a lower roll provided movably between a curl correcting position where the direction of the transport belt is bent convexly toward the upper roll.

  A second aspect of the present invention is the printing apparatus according to the first aspect, wherein a plurality of the print heads are arranged at intervals in the paper conveyance direction, and the curl correction is provided at each upstream position of the plurality of print heads. Each means is arranged.

  A third aspect of the present invention is the printing apparatus according to the first aspect, wherein the curl correction means positions the lower roll of the curl correction means in a non-correction position when the printing paper is a stiff paper. It is characterized by making it.

  A fourth aspect of the present invention is the printing apparatus according to the first aspect, wherein the curl correcting means is a non-correcting position of the lower roll of the curl correcting means in the case of single-sided printing and during surface printing of double-sided printing. It is located in.

  A fifth aspect of the present invention is the printing apparatus according to the first aspect, wherein the curl correction means positions the lower roll of the curl correction means at a curl correction position during back-side printing of double-sided printing. To do.

  A sixth aspect of the present invention is the printing apparatus according to the first aspect, wherein the curl correction position of the curl correction means is variable to a plurality of positions.

  According to the first aspect of the present invention, the curl correction position of the lower roll can be set freely, and a convex curl correction path having a desired size can be formed. In the case of double-sided printing, the ink adhering surface immediately after printing is not strongly pressed against the lower roll, so that it does not become a defective printing surface.

  According to the second aspect of the present invention, curling of the printing paper is corrected before being conveyed to each printing head, so that printing paper that is not curled is reliably conveyed to each printing head.

  According to the invention of claim 3, a stiff printing paper generally does not curl. Therefore, it is possible to perform proper printing without adding a curl detecting means.

  According to the invention of claim 4, in the case of single-sided printing and double-sided printing, printing paper is generally not curled. Therefore, it is possible to perform proper printing without adding a curl detecting means.

  According to the invention of claim 5, in the case of the back side printing of the double sided printing, the printing paper is generally curled. Therefore, it is possible to perform proper printing without adding a curl detecting means.

  According to the sixth aspect of the invention, it is possible to correct the curl according to the curl degree of the printing paper.

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

  1 to 3 show an embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a main part of a printing apparatus when a curl correction unit is located at a non-correction position. FIG. FIG. 3 is a schematic diagram of the main part of the curl correcting means.

  As shown in FIGS. 1 and 2, the printing apparatus includes a paper feed unit (not shown) that feeds the printing paper P stacked on a paper feed table (not shown) one by one, and the paper feed unit. The image forming unit 1 that performs an image forming process on the fed printing paper P, and the paper discharge that conveys the printing paper P image-formed by the image forming unit 1 and stacks it on a paper discharge tray (not shown) Part (not shown).

  The image forming unit 1 includes a platen 2 having an upper surface as a conveyance path, a sheet conveyance unit 3 that conveys the printing sheet P fed from the sheet feeding unit along the conveyance path by the conveyance belt 3c, and the conveyance belt 3c. A paper suction means (not shown) for sucking the print paper P, four print heads 4 provided on the upper surface side of the transport path of the paper transport means 3, and a position immediately upstream of each print head 4 are arranged. And a curl correcting means 5 for correcting the curl of the printing paper P.

  The platen 2 is formed with four recesses 2a for arranging lower rolls 11 described later.

  The sheet conveying means 3 is provided between a pair of driven pulleys 3 a and 3 a that are rotatably provided at positions outside both ends of the platen 2, and between the pair of driven pulleys 3 a and 3 a and at a position below the platen 2. A drive pulley 3b, an infinite end conveyor belt 3c stretched between the drive pulley 3b and the pair of driven pulleys 3a, 3a, and a drive motor (not shown) for rotationally driving the drive pulley 3b. ing. By driving the drive motor, the transport belt 3c moves in the paper transport direction along the transport path.

  The four print heads 4 are of an ink jet type that ejects, for example, yellow, cyan, magenta, and black water-based inks, respectively.

  Each curl correcting means 5 is disposed on the upper surface (one surface) side of the conveyance path of the conveyance belt 3c, and a pair of upper rolls 10 and 10 provided at intervals in the sheet conveyance direction, and the conveyance path of the conveyance belt 3c. And a lower roll 11 disposed between the pair of upper rolls 10 and 10 on the lower surface (the other surface) side. The lower roll 11 has a non-correcting position (the position in FIG. 1 and the broken line position in FIG. 3) where the moving direction of the conveying belt 3c is not bent, and a curl correction that bends the moving direction of the conveying belt 3c in a convex shape toward the upper roll 10. It is provided so as to be movable between positions (position in FIG. 2, position in solid line in FIG. 3). In the uncorrected position, each lower roll 11 is disposed in the recess 2 a of the platen 2.

  In the above configuration, as shown in FIG. 1, when printing a non-curled printing paper P, each curl correcting means 5 is positioned at a non-correcting position. The printing paper P fed from the paper feed unit passes through the curl correcting means 5 and the print heads 4 alternately by moving on the transport path along the transport belt 3c. The printing paper P simply passes through the position of each curl correcting means 5 and undergoes image formation processing by ejecting ink of each color when passing under the printing head 4.

  Here, the non-curled printing paper P passes through a position that is separated from each printing head 4 by a predetermined distance, so that proper printing is performed. The printed printing paper P1 is discharged to the paper discharge unit.

  As shown in FIG. 2, when printing the curled printing paper P, each curl correcting means 5 is positioned at the curl correcting position. The printing paper P1 fed from the paper feeding unit passes through the curl correcting means 5 and the printing heads 4 alternately by moving on the transporting path along the transporting belt 3c. As shown in FIG. 3, the printing paper P passes through the curl correction path that is convex upward at the position of each curl correction means 5. Therefore, the curl is corrected when passing through this curl correction path. The corrected printing paper P is conveyed to each printing head 4. Then, an image forming process is performed by ejecting ink of each color when passing under each print head 4.

  Here, since the curl of the printing paper P1 is not corrected and curled, the print paper P1 passes through a position separated by a predetermined distance with respect to each print head 4, so that proper printing is performed. The printed printing paper P1 is discharged to the paper discharge unit.

  As described above, in this embodiment, the curl correcting means 5 provided on the upstream side of each print head 4 is composed of the pair of upper rolls 10 and 10 and the lower roll 11 disposed therebetween. Thus, a desired convex curl correction path can be formed, so that the curl of the printing paper P can be reliably corrected. Further, in the case of backside printing by double-sided printing, the ink adhering surface immediately after printing is not strongly pressed against the lower roll 11, so that it does not become a defective printing surface.

  Further, since the curl correcting means 5 is provided at the upstream position of each print head 4, the curl of the printing paper P is corrected before being conveyed to each print head 4. Unprinted printing paper P can be reliably conveyed.

  Further, the curl correction position of the lower roll 11 of the curl correction means 5 is one in this embodiment, but it may be variable to a plurality of positions. If comprised in this way, the curl correction according to the curl degree of the printing paper P is possible. For example, when printing with a changing printing rate is performed continuously, the curling amount of the printing paper P also changes. Therefore, if the curl correction position is varied according to the curling amount, each printing paper P Appropriate curl correction is possible every time.

  Further, the degree of curl correction can be achieved to some extent by changing not only the position of the lower roll 11 but also the diameter of the lower roll 11.

  Further, the presence or absence of curling of the printing paper P may be determined by providing a curling detection means in the transport path in front of the image forming unit 1. Further, without the curl detecting means, the presence or absence of curl may be determined according to the type of printing paper P and the printing state.

  That is, when judging by the type of the printing paper P, when the printing paper P is a stiff thick paper, it is judged that the printing paper P is not curled, and printing is performed with the curl correcting means 5 as the non-correcting position. This is because the stiff printing paper P is generally difficult to curl.

  Further, when the determination is made based on the printing state, that is, in the case of single-sided printing or in the case of double-sided surface printing, it is determined that the printing paper P is not curled, and printing is performed with the curl correction means 5 set to the non-correction position. Apply. In the case of double-sided printing, it is determined that the printing paper is curled, and printing is performed with the curl correction means 5 as the curl correction position. Furthermore, in the case of single-sided printing and double-sided surface printing, the printing paper is generally not curled, and in the case of double-sided printing backside printing, the printing paper is generally printed by surface printing. This is because it is curled.

  In the above-described embodiment, the case where the printing apparatus has four print heads 4 and performs color printing has been described. However, the present invention can be applied to a case where only a single print head is provided and single color printing is performed. Of course, it can be applied.

1 is a schematic configuration diagram of a main part of a printing apparatus in a case where an embodiment of the present invention is shown and curl correction means is located at a non-correction position. 1 is a schematic configuration diagram of a main part of a printing apparatus in a case where an embodiment of the present invention is shown and a curl correction unit is located at a curl correction position. FIG. 1 is a configuration diagram of a main part of a curl correction unit according to an embodiment of the present invention. It is a schematic block diagram of the conventional printing apparatus. It is a block diagram of the principal part of the conventional curl correction means. It is a perspective view of the curled printing paper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image formation part 3 Paper conveyance means 3c Conveyance belt 4 Print head 5 Curl correction means 10 Upper roll 11 Lower roll

Claims (6)

A conveyance belt that moves along the conveyance path, and is provided on one side of the conveyance path of the sheet conveyance means and a sheet conveyance means that conveys the printing paper fed on the conveyance belt in the sheet conveyance direction. A print head, and a curl correcting means that is disposed upstream of the print head in the transport path and corrects the curl of the print paper,
The curl correcting means is disposed on one side of the transport belt and is provided with a pair of upper rolls provided at intervals in the paper transport direction; on the other side of the transport belt and on the pair of upper rolls A lower roll that is arranged between the non-correction position that does not bend the direction of the transport belt and the curl correction position that bends the direction of the transport belt convexly toward the upper roll; A printing apparatus comprising: The printing apparatus according to claim 1,
A plurality of the print heads are arranged at intervals in the paper conveyance direction, and the curl correcting means is arranged at each upstream position of the plurality of print heads. The printing apparatus according to claim 1,
The curl correcting unit is configured to position the lower roll of the curl correcting unit in a non-correcting position when the printing sheet is a stiff sheet. The printing apparatus according to claim 1,
The curl correcting unit is configured to place the lower roll of the curl correcting unit in a non-correcting position in the case of single-sided printing and during surface printing of double-sided printing. The printing apparatus according to claim 1,
The said curl correction means positions the said lower roll of the said curl correction means in a curl correction position at the time of back surface printing of double-sided printing. The printing apparatus according to claim 1,
The curl correction position of the curl correction means can be changed to a plurality of positions.

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