JP4186803B2 - Printing apparatus and printing method - Google Patents

Description

  The present invention relates to a printing apparatus and a printing method therefor, and more particularly to a printing apparatus and a printing method in which a sheet member is intermittently fed toward an image forming area on a conveyance path.

  2. Description of the Related Art Printing apparatuses used for printers, copiers, facsimiles, and the like are configured to form an image based on image information on one main surface of a sheet body such as paper, plastic thin plate, or cloth that is conveyed.

  As such a printing apparatus, paper is intermittently fed (intermittent feed) at a predetermined feed amount in the carrying direction, and printing that reciprocates in the direction (main scanning direction) perpendicular to the carrying direction (sub-scanning direction) when feeding is stopped. 2. Related Art An ink jet printer that discharges ink from a head and forms (prints) an image on a sheet is known.

For example, in the ink jet printer disclosed in Patent Document 1, the sheet is fed in the image forming area only by the transport roller unit provided on the upstream side of the transport path from the image forming area.
JP 2003-159841 A

  However, as in the technique of Patent Document 1, in the case where the conveyance path on the downstream side from the image forming area is not provided with a means that contributes to feeding of the paper in the image forming area, the paper sent out by the feeding means is, for example, a suction member Due to the resistance such as adsorption by the sheet, a force that hinders feeding acts and the sheet bends. As a result, there is a possibility that a minus error corresponding to the deflection of the sheet occurs with respect to the predetermined feeding amount, and the feeding accuracy of the sheet to the image forming area is lowered.

  Therefore, the main object of the present invention is to increase the height of the sheet body in the image forming area even when the downstream conveying path from the image forming area is not provided with means for contributing to the feeding of the sheet body in the image forming area. To provide a printing apparatus and a printing method for feeding with feeding accuracy.

In order to achieve the above-described object , the printing apparatus according to claim 1 forms an image in an image forming area of a conveyance path on one main surface of a sheet body that is intermittently fed at a predetermined feed amount in the conveyance direction. In a printing apparatus that does not include means for applying a force for feeding the sheet body in the image forming area to the conveyance path on the downstream side from the image forming area, the one main surface of the sheet body is flattened in the image forming area An adsorbing member that is provided in the conveyance path for adhering the other main surface of the sheet body and maintains the sheet body at a feed amount that is greater than or equal to a predetermined feed amount toward the image forming area every time the sheet body is intermittently fed. It is characterized by comprising feeding means for pulling back the sheet body to the upstream side of the conveying path by an excess feeding amount with respect to a predetermined feeding amount.

According to a second aspect of the present invention, there is provided a printing method in which an image is formed in an image forming area of a conveyance path on one main surface of a sheet body that is intermittently fed at a predetermined feed amount in the conveyance direction, and the sheet body in the image forming area is formed. A printing method in which no feeding force is applied from the downstream side of the image forming area, and the other main surface of the sheet body is sucked onto the conveyance path in order to keep the one main surface of the sheet body flat in the image forming area. the while being, pulled back sheet toward the image forming region first step for feeding a predetermined feed amount or feed amount, and the upstream side of the excess feed amount by the conveying path of the sheet material for a given feed amount e Bei two steps, performing the first step and the second step each time the intermittent feeding operation of the sheet.

In the printing apparatus according to claim 1, the sheet body is directed toward the image forming area in consideration of a maximum amount of deflection generated in the sheet and a maximum negative error with respect to the predetermined feed amount in advance. The sheet body is pulled back to the upstream side of the transport path by an amount that is excessive with respect to the predetermined feed amount. By repeating this operation, it is possible to remove the bend generated in the sheet body and absorb the negative error generated with respect to the predetermined feed amount, and to ensure that the sheet body is directed to the image forming area with the predetermined feed amount. Can send. The same applies to the printing method according to claim 2 .

In order to improve the processing capability of the printing apparatus, it is necessary to make the image forming area as long as possible in the conveying direction of the sheet. In the case of a printing apparatus used by pulling out a sheet body from a magazine or the like that stores a long sheet body wound in a roll shape, the sheet body curls in the image forming area when the image forming area is elongated in the sheet conveying direction, There is a possibility that the quality of the image formed on the one main surface of the sheet body may deteriorate. In order to prevent this, an adsorption member that adsorbs the other main surface of the sheet member to the surface and keeps the one main surface of the sheet member flat in the image forming region is often provided on the conveyance path. By providing the suction member on the transport path, the flatness of the one main surface of the sheet body can be secured in the image forming area, but the suction by the suction member becomes a sheet feeding resistance and the sheet body is bent, and a predetermined amount is generated. A negative error may occur randomly with respect to the feed amount. In the printing apparatus according to claim 1 , the sheet body is directed toward the image forming area in consideration of the maximum deflection of the sheet generated by the suction member and the maximum negative error with respect to a predetermined feed amount. The sheet is fed by a feed amount that is equal to or greater than a predetermined feed amount, and the sheet body is pulled back to the upstream side of the transport path by an excess feed amount with respect to the predetermined feed amount. As a result, even when the other main surface of the sheet body is adsorbed to the adsorbing member and the adsorbing force becomes the feeding resistance of the sheet body, the bending that occurs in the sheet body is removed and a minus is generated for a predetermined feed amount. Thus, the sheet member can be reliably fed toward the image forming area with a predetermined feed amount. The same applies to the printing method according to claim 2 .

  In the present specification, the “sheet body” includes not only paper used in a general printing apparatus but also widely includes cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like.

  According to the present invention, the sheet member can be fed to the image forming area with high feeding accuracy.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
A case where the present invention is applied to an ink jet printer will be described.
An ink jet printer 10 shown in FIG. 1 includes a paper magazine (paper cassette) 14, an advance roller unit 16, an ink jet printing unit 18, a pressure roller unit 20, and a cutting unit 22 in a substantially rectangular housing 12. , And a discharge roller unit 24. As will be described later, the operation of each part of the ink jet printer 10 is controlled by a controller 78 (see FIG. 5) disposed in the housing 12.

The paper magazine 14 is a substantially rectangular parallelepiped housing, in which winding sections 28 each having a long paper 26 wound in a roll shape are housed, and can be loaded into or removed from the housing 12 (detachable) Possible). The winding portion 28 of the paper 26 stored in the paper magazine 14 is placed on a driving roller 30 that can rotate the winding portion 28 and a driven roller 32 that rotates together with the winding portion 28. Here, when the driving roller 30 is rotationally driven by the controller 78, the driving roller 30 rotates the winding portion 28 in the direction in which the paper 26 is unwound or the direction in which the paper 26 is taken up, and sends out the paper 26. Or it can be rewound. Note that after the leading edge of the paper 26 is supplied to the advance roller unit 16, the paper 26 is conveyed by the advance roller unit 16.

  The advance roller unit 16 is for conveying the paper 26 before being cut by the cutting unit 22, and as shown in FIG. 2, a motor 34 controlled by a controller 78 and a paper feed driven by the motor 34. A roller 36. The paper feed roller 36 is arranged so as to correspond to the conveyance path of the paper 26 along the arrow W direction (direction perpendicular to the arrow L direction: main scanning direction). Further, as shown in FIG. 1, the advance roller unit 16 includes pressure-bonding rollers 36 a and 36 b provided at positions corresponding to the paper feed roller 36. The pressure-bonding rollers 36 a and 36 b respectively sandwich the paper 26 with the paper feed roller 36 and rotate as the paper feed roller 36 rotates. The advance roller unit 16 intermittently feeds the paper 26 unwound from the winding unit 28 by a predetermined feed amount in the direction of arrow L (conveyance direction: sub-scanning direction), and causes the inkjet printing unit 18 and the cutting unit 22 to move. Pass sequentially.

  Here, as the motor 34, for example, a motor controlled by a pulse signal input at a constant cycle, such as a stepping motor or a servo motor, is used. The pulse signal is an electric signal output from a pulse oscillator (not shown) of the controller 78 and input to the motor 34 via a driver (not shown), and the pulse width per pulse is determined by the input time of the electric signal. In the motor 34 controlled by the pulse signal, the rotation direction of the drive shaft is determined by the sign of the input pulse signal, and the rotation angle of the drive shaft is increased or decreased by the pulse width per pulse of the input pulse signal. The rotational speed of the drive shaft increases or decreases depending on the frequency of the input pulse signal.

  The ink jet printing unit 18 includes a carriage 38. As shown in FIG. 3, the carriage 38 is fixed to the endless belt 40 of the drive mechanism 39 and is movable along the guide shaft 42. The endless belt 40 is wound around pulleys 44a and 44b, and a drive shaft of a carriage drive motor 46 is connected to the pulley 44a. Accordingly, the carriage 38 reciprocates in the direction of arrow W along the guide shaft 42 as the motor 46 rotates. The carriage 38 holds a print head 48 and an ink tank 50 as a container for storing ink.

  The print head 48 is provided with a number of discharge nozzles 48 a that can discharge color inks such as yellow (yellow), magenta (red purple), cyan (blue green), and black on the surface facing the paper 26. ing. Accordingly, the print head 48 causes the color ink supplied from the ink tank 50 toward the front surface (upper surface in FIG. 2) of the conveyed paper 26 based on the signal from the controller 78 from the many discharge nozzles 48a. A desired color image can be printed by discharging each of them. The print head 48 may be capable of printing a black and white image.

  The ink jet printing unit 18 ejects liquid ink from the nozzles dot by dot to print on the paper 26, and may adopt any one of the piezo jet method, the thermal jet method, and other methods. Good.

  As described above, the carriage 38 holds the print head 48 and reciprocates together with the print head 48 in the arrow W direction. Therefore, the print head 48 ejects ink toward the surface of the paper 26 while reciprocating in the arrow W direction. FIG. 2 shows a case where the print head 48 is at a standby position (home position) when printing is not performed.

  Further, the inkjet printing unit 18 includes a suction plate 52. The suction plate 52 has a paper support surface that is the same height as the conveyance surface of the paper 26, and supports the paper 26 that is disposed to face the print head 48. Therefore, the print head 48 prints on the surface of the paper 26 on the suction plate 52 while reciprocating along the arrow W direction while facing the surface of the suction plate 52. In FIG. 2, an area (printable area) that can be opposed to the print head 48 on the suction plate 52 and is printed is indicated by an alternate long and short dash line X.

  Here, a large number of circular suction holes 54 are formed almost uniformly in the suction plate 52. The suction fan 56 is opposed to the print head 48 across the conveyance path of the paper 26 and is disposed at a position corresponding to the region where the suction holes 54 of the suction plate 52 are formed. Is adsorbed through the adsorption holes 54. Accordingly, the sheet 26 facing the print head 48 is conveyed in close contact with the suction plate 52 by being sucked by the suction fan 56 disposed on the back surface (lower surface in FIG. 1), and spaced from the print head 48. Has become constant. Thereby, when the paper 26 is curled, it is possible to suppress the occurrence of printing defects due to a change in the distance from the print head 48 due to a part of the paper 26 being greatly separated from the suction plate 52.

  Further, ink receiving portions 58a and 58b are arranged at positions where the suction plate 52 is sandwiched in the direction of the arrow W. The ink receiving portions 58 a and 58 b are for receiving ink discharged from the discharge nozzle 48 a by the flushing operation of the print head 48.

  Here, a suction device 60a as shown in FIG. 4 is disposed below the ink receiving portion 58a. The suction device 60a has a cylindrical portion 62a and a fan 64a. The cylindrical portion 62a has one end connected to the lower end of the ink receiving portion 58a, and extends downward from the end and then bends in an obliquely upward direction. The bent portion 62a is bent. A fan 64a is disposed at the upper end of the unit. A plurality of partition walls 66a are arranged in the cylindrical portion 62a.

  Therefore, when the fan 64a of the suction device 60a is driven by the controller 78, the air flows into the cylindrical portion 62a from the end where the ink receiving portion 58 is connected toward the end where the fan 64a is disposed. Will occur. Accordingly, the ink discharged to the ink receiving portion 58a by the flushing operation of the print head 48 is sucked into the cylindrical portion 62a by the air flow in the cylindrical portion 62a. The ink sucked into the cylindrical portion 62a is discharged from a discharge pipe 68a provided near the lower end portion of the cylindrical portion 62a to a waste ink receiver (not shown).

  A suction device 60b similar to the above-described suction device 60a is also disposed below the ink receiving portion 58b. When the fan 64b of the suction device 60b is driven by the controller 78, the flushing operation of the print head 48 is performed. Ink discharged to the ink receiving portion 58b is sucked. The configurations of the suction devices 60a and 60b can be arbitrarily changed within a range in which the ink discharged to the ink receiving portions 58a and 58b by the flushing operation of the print head 48 can be sucked.

  The pressure roller unit 20 is for sandwiching the paper 26 conveyed between the inkjet printing unit 18 and the cutting unit 22. By disposing the pressure roller unit 20 between the inkjet printing unit 18 and the cutting unit 22, it is possible to appropriately perform image printing by the inkjet printing unit 18 and cutting of the paper 26 by the cutting unit 22.

  The cutting unit 22 has a moving blade 70 disposed on the same side as the print head 48 with respect to the paper 26 and a fixed blade 72 disposed so as to face the moving blade 70 with the paper 26 interposed therebetween. . Both the moving blade 70 and the fixed blade 72 are short blades having a width slightly larger than the interval between the end portions of the paper 26 in the arrow W direction. The moving blade 70 is controlled by a controller 78 so as to be close to or separated from the fixed blade 72, and the printed paper 26 that has been conveyed from the upstream side of the conveyance path is transferred to the fixed blade 72. It is possible to cut along the direction of arrow W by the interaction with 72. By being cut in this way, the printed paper 26 is divided into a predetermined length.

  The discharge roller unit 24 has a drive roller pair 74 controlled by a controller 78, conveys the printed paper 26 after being cut by the cutting unit 22, and discharges it from the discharge port 76. The drive roller pair 74 of the discharge roller unit 24 is arranged so as to correspond to the conveyance path of the paper 26 along the arrow W direction, similarly to the paper feed roller 36 of the advance roller unit 16.

Here, a control system of the ink jet printer 10 will be described with reference to FIG.
The controller 78 includes a CPU 78a, a ROM 78b, and a RAM 78c. The ROM 78b stores a program for controlling the operation of the ink jet printer 10 and the like. The CPU 78a controls the operation of the ink jet printer 10 by calling and executing a predetermined program stored in the ROM 78b. The RAM 78c is developed with a program for controlling the ink jet printer 10, and stores processing results by the program, temporary data for processing, and the like, and is used as a work area of the CPU 78a.

  The controller 78 includes a motor 80 connected to the drive roller 30 of the paper magazine 14, a motor 34 connected to the paper feed roller 36 of the advance roller unit 16, a print head 48 of the inkjet printing unit 18, and a carriage 38. A drive mechanism 39 for reciprocating movement, a motor 82 connected to the suction fan 56, motors 84a and 84b connected to the fans 64a and 64b, and a motor 86 connected to the moving blade 70 of the cutting unit 22, respectively. The motor 88 connected to the drive roller pair 74 of the discharge roller unit 24 is connected to each other.

  Therefore, the controller 78 performs predetermined processing on the image signal supplied from an input interface (not shown), and supplies the print signal including the image data corresponding to the image to be printed to the print head 48 of the inkjet printing unit 18. The controller 78 also feeds the paper 26 by the paper magazine 14, the advance roller unit 16 and the discharge roller unit 24, moves the carriage 38, discharges ink from the print head 48, and cuts the paper 26 by the cutting unit 22. Control timing etc. Further, the controller 78 controls the suction fan 56 to suck the paper 26 through the suction holes 54 of the suction plate 52, and the suction devices 60a and 60b connected to the ink receiving portions 58a and 58b, respectively. Control.

  In the ink jet printer 10 configured as described above, the paper 26 unwound from the winding unit 28 is intermittently sent in the direction of arrow L by the advance roller unit 16, and the print head 48 of the ink jet printing unit 18. The print head 48 prints an image in a state where the print head 48 is disposed in the printable area X facing the front.

  At this time, the print head 48 reciprocates in the direction of arrow W while facing the paper 26, and the print head 48 faces the surface of the paper 26 when the print head 48 faces the paper 26 by reciprocation during printing. When the print head 48 is in the vicinity of both ends of the reciprocating movement during printing, the advance roller unit 16 intermittently feeds the paper 26 by a predetermined feed amount. In this way, the feeding operation of the paper 26 of the advance roller unit 16 and the forward or backward movement of the print head 48 in the direction of the arrow W are alternately repeated, while ink is ejected onto the paper 26 and the paper 26 is ejected. Printing is performed.

Further, with reference to FIG. 6 and FIG. 7, the one-time feeding operation of the advance roller unit 16 that intermittently feeds the paper 26 will be described in detail.
Here, it is assumed that the feed amount of the paper 26 per feed operation by the advance roller unit 16 is set to 3.0 mm. Further, it is assumed that the paper 26 unwound from the winding unit 28 has already been sent onto the suction plate 52 by the advance roller unit 16.

  As shown in FIG. 6A, first, based on an instruction from the controller 78, the drive shaft of the motor 34 is rotationally driven in a predetermined rotation direction and rotation angle, and the paper feed roller 36 and the pressure roller 36a are respectively moved to the arrows R1, R1. Rotate in R1a direction. Along with this, the feeding point P of the paper 26 sandwiched between the paper feeding roller 36 and the pressure roller 36a is fed in the direction of arrow L from the position A which is the feeding start position.

  Then, as shown in FIG. 6B, the feed point P is fed from the position A to the position B that is separated by a distance of 3.1 mm in the direction of the arrow L, and the rotation of the paper feed roller 36 and the pressure roller 36a is stopped.

  By feeding the feeding point P in the direction of arrow L, the leading edge 26a of the paper 26 is also fed in the direction of arrow L from the position A1 on the suction plate 52 as shown in FIG. At this time, the sheet 26 is sucked in the direction of the arrow F by the suction fan 56 when passing over the suction hole 54 disposed on the back side thereof, and is difficult to advance in the direction of the arrow L.

  Then, as shown in FIG. 7B, the sheet 26 may be bent at a portion not sucked by the fan 56. In this case, when the rotation of the paper feed roller 36 and the pressure roller 36a is stopped, the tip 26a cannot reach the position B1 that is spaced 3.1 mm from the position A1 on the suction plate 52, and the position B1 and the position C1. (Position at a distance of 0.1 mm from the position B1 in the direction opposite to the arrow L direction). That is, at the leading edge 26a of the paper 26, a minus error occurs within a range of 0.1 mm with respect to the feed amount (3.1 mm).

  Returning to FIG. 6B, the motor 34 is then driven to rotate at a predetermined rotation direction and rotation angle based on an instruction from the controller 78, and the paper feed roller 36 and the pressure roller 36a are moved in the directions of arrows R2 and R2a (arrows), respectively. Rotate in the opposite direction to R1 and R1a.

  Accordingly, as shown in FIG. 6 (c), the delivery point P is pulled back from position B to position C (position separated from position B by a distance of 0.1 mm in the direction opposite to the arrow L direction), The rotation of the paper feed roller 36 and the pressure roller 36a is stopped.

  When the feeding point P is pulled back in the direction opposite to the arrow L direction, the paper 26 on the suction plate 52 is also pulled back in the direction opposite to the arrow L direction as shown in FIG. The deflection is removed. And the front-end | tip 26a which stopped between position B1 and position C1 is pulled back to position C1, and stops.

  That is, the paper feed roller 36 and the pressure roller 36a feed the paper 26 at the feed point P in the direction of the arrow L at a feed amount of 3.1 mm, and the leading edge of the paper 26 is bent with respect to the feed amount at the feed point P. In consideration of the error generated in 26a in advance, the sheet is pulled back in the direction opposite to the arrow L direction with a pullback amount of 0.1 mm. As a result, the bending generated in the paper 26 is removed, the leading edge 26a stops at the position C1, and the paper 26 is fed at a predetermined feed amount of 3.0 mm.

  In FIG. 7, the description has been made by paying attention to the leading edge 26 a of the paper 26, but as a result of a series of feeding operations of the advance roller unit 16 on the suction plate 52, a predetermined feeding amount is taken regardless of the location of the paper 26. Needless to say, it is sent at 3.0 mm.

  Further, the amount of pulling back the feeding point P of the paper 26 is as small as 0.1 mm, and the influence on the processing capability of the ink jet printer 10 is small.

  According to such an ink jet printer 10, even when the paper 26 is attracted to the suction plate 52 and the suction force becomes a feeding resistance of the paper 26, the advance roller unit 16 sends out a predetermined feed amount or more. The sheet 26 is fed out in the direction of the arrow L by the amount, and the sheet 26 is pulled back in the direction opposite to the arrow L direction by a surplus with respect to the predetermined feeding amount, thereby removing the bending generated in the sheet 26 and feeding out the feeding point P. The error generated at the leading edge 26a with respect to the amount can be absorbed, and the paper 26 can be reliably sent to the ink jet printing unit 18 with a predetermined feed amount, and the quality of the image printed on the surface of the paper 26 can be improved. Can be improved.

  It should be noted that the feed amount and the return amount of the feed point P of the paper 26 in the above-described embodiment, and thus the feed amount of the paper 26 are merely examples, and are not limited thereto. For example, the pulse signal input to the motor 34 can be changed in accordance with the type of the paper 26, the resolution of the image printed on the paper 26, and the like, and the delivery amount and the withdrawal amount of the delivery point P of the paper 26 can be set as appropriate. .

  In the above-described embodiment, the ink jet printer having one conveyance path has been described. However, the present invention has two or more conveyance paths, and each independently forms a print on a sheet body in parallel. It can also be applied to devices.

  In the above-described embodiment, an ink jet printer that forms an image on a long sheet of paper has been described. However, the present invention forms an image on a sheet body having a predetermined length while the sheet body is conveyed. The present invention can also be applied to a printing apparatus that performs the above.

1 is an illustrative view showing an ink jet printer according to an embodiment to which the present invention is applied. FIG. 2 is a plan view showing a part of the ink jet printer of FIG. 1. FIG. 2 is a perspective view illustrating a schematic configuration of a print head and its periphery of the ink jet printer of FIG. 1. It is an illustration figure which shows the suction device used for the ink jet type printer of FIG. FIG. 2 is a block diagram illustrating a control system of the ink jet printer of FIG. 1. It is an illustration figure for demonstrating the feed operation of an advance roller unit. It is an illustration for demonstrating the movement on the adsorption | suction plate of the paper sent by an advance roller unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet printer 14 Paper magazine 16 Advance roller unit 18 Inkjet printing unit 26 Paper 26a Tip 36 Paper feed roller 36a Pressure roller 38 Carriage 39 Drive mechanism 48 Print head 52 Suction plate 54 Suction hole 56 Suction fan 78 Controller P Sending point

Claims (2)

An image is formed in the image forming area of the conveying path on one main surface of the sheet body that is intermittently fed at a predetermined feed amount in the conveying direction, and in the image forming area in the conveying path downstream from the image forming area. In a printing apparatus that does not include means for applying a force for feeding the sheet body to the sheet body ,
An adsorbing member that is provided in the conveyance path to adsorb the other main surface of the sheet body in order to keep the one main surface of the sheet body flat in the image forming region; and
Each time the sheet body is intermittently fed, the sheet body is fed toward the image forming area by a feed amount that is equal to or greater than the predetermined feed amount, and the sheet body is surplus with respect to the predetermined feed amount. A printing apparatus, comprising: a feeding unit that pulls back to the upstream side of the conveyance path. An image is formed in the image forming area of the conveying path on one main surface of the sheet body that is intermittently fed at a predetermined feeding amount in the conveying direction, and the force for feeding the sheet body in the image forming area is the image. A printing method not provided from the downstream side of the forming area,
While adsorbing the other major surface of the sheet on the conveying path one major surface of the sheet by the image forming region in order to keep the plane, the predetermined feed amount of the sheet toward the image forming region e Bei the first step, and a second step of returning to the upstream side of the transport path by excessive feeding amount of the sheet with respect to the predetermined feed amount feeding the above feed amount,
A printing method in which the first step and the second step are performed each time the sheet body is intermittently fed .

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