JP2017065063A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet printer which can alleviate the reduction in the printing quality while alleviating restriction of the layout of an ink jet head.SOLUTION: An ink jet printer 1 includes: an ink jet head 31 which discharges ink to a consecutively-conveyed web; a pair of platen rollers which is arranged on the upstream side and downstream side of the ink jet head 31 at the opposite side of the ink jet head 31 having the web therebetween, supports the web and is rotated following the web; a timing belt which synchronously rotates the pair of platen rollers; a storage unit 4 which stores profile data indicating an eccentric amount at each prescribed rotation angle of the pair of platen rollers and an impact time deviation amount of ink according to the distance between the respective platen rollers and the ink jet head 31 in the conveyance direction of the web; and a control unit 5 which controls the discharge timing of ink in the ink jet head 31 by using the profile data.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inkjet printing apparatus that prints by ejecting ink from an inkjet head.

  2. Description of the Related Art An ink jet printing apparatus that prints by ejecting ink from an ink jet head while continuously transporting a belt-shaped web made of paper, film, metal foil or the like as a print medium is known.

  In such an ink jet printing apparatus, a configuration in which a web is supported by a platen roller that is driven and rotated by a web being conveyed below the ink jet head is generally used. However, in this configuration, the web moves up and down due to the eccentricity of the platen roller, and the head gap, which is the distance between the ink jet head and the web, may fluctuate. When the head gap fluctuates, the landing position of the ink is displaced, and the print image quality may be deteriorated.

  On the other hand, in the ink jet printing apparatus of Patent Document 1, the platen rollers on the upstream side and the downstream side of the ink jet head that are driven to rotate while supporting the web appear to have opposite eccentric phases. It is linked to. The ink jet head is disposed at an intermediate position between the upstream platen roller and the downstream platen roller. Thereby, the eccentricity of both platen rollers is canceled at the position of the ink jet head, and the fluctuation of the head gap is reduced.

JP2011-148225A

  However, in the technique of Patent Document 1, since the inkjet head needs to be disposed at an intermediate position between the upstream platen roller and the downstream platen roller, the layout of the inkjet head is limited. This may make it difficult to reduce the size of the apparatus.

  The present invention has been made in view of the above, and an object of the present invention is to provide an ink jet printing apparatus capable of reducing a decrease in print image quality while reducing restrictions on the layout of the ink jet head.

  In order to achieve the above object, a first feature of an ink jet printing apparatus according to the present invention is that an ink jet head that discharges ink onto a continuously-formed belt-like print medium and an ink jet head opposite to the ink jet head sandwiching the print medium are provided. A pair of platen rollers disposed on the upstream side and the downstream side of the inkjet head in the transport direction of the print medium, supporting the transported print medium and rotating following the print medium, and the pair of platen rollers Ink landing according to the connecting member for synchronously rotating the plate, the amount of eccentricity for each predetermined rotation angle of the pair of platen rollers, and the distance between the platen roller and the inkjet head in the conveyance direction of the print medium A storage unit for storing profile data indicating an amount of time shift, and the profile In that a control unit which controls the ejection timing of ink in the ink-jet head using the data.

  A second feature of the ink jet printing apparatus according to the present invention is that the platen roller on the downstream side of the pair of platen rollers has a larger outer diameter than the platen roller on the upstream side.

  A third feature of the inkjet printing apparatus according to the present invention is that an inkjet head that ejects ink onto a continuously-formed belt-like print medium and conveyance of the print medium on the opposite side of the inkjet head that sandwiches the print medium. A pair of platen rollers which are respectively arranged on the upstream side and the downstream side of the inkjet head in the direction and support the conveyed print medium and rotate following the print medium, and for each predetermined rotation angle of the platen roller A storage unit that stores data indicating an eccentricity amount, an eccentricity amount for each predetermined rotation angle of each of the platen rollers, and a distance between each of the platen roller and the inkjet head in the conveyance direction of the print medium Based on the above, the ink ejection timing in the inkjet head is controlled It lies in and a that controller.

  According to the first feature of the inkjet printing apparatus according to the present invention, the control unit includes the eccentric amount for each predetermined rotation angle of the pair of platen rollers and the platen roller and the inkjet head in the conveyance direction of the print medium. The ink ejection timing in the inkjet head is controlled using profile data indicating the amount of landing time difference of the ink according to the distance between them. Thereby, regardless of where the inkjet head is disposed between the pair of platen rollers, it is possible to suppress the landing position deviation of the ink due to the fluctuation of the head gap caused by the eccentricity of the platen roller. As a result, it is possible to reduce the deterioration of the print image quality while reducing the restrictions on the layout of the inkjet head.

  According to the second feature of the ink jet printing apparatus according to the present invention, since the outer diameter of the downstream platen roller is larger than that of the upstream platen roller, occurrence of flutter due to a decrease in the tension of the printing medium is suppressed. As a result, it is possible to further reduce the decrease in print image quality.

  According to the third feature of the ink jet printing apparatus according to the present invention, the control unit includes the eccentric amount for each predetermined rotation angle of each platen roller and the platen roller and the ink jet head in the transport direction of the print medium. Based on the distance, the ink ejection timing in the inkjet head is controlled. Thereby, regardless of where the inkjet head is disposed between the pair of platen rollers, it is possible to suppress the landing position deviation of the ink due to the fluctuation of the head gap caused by the eccentricity of the platen roller. As a result, it is possible to reduce the deterioration of the print image quality while reducing the restrictions on the layout of the inkjet head.

It is a block diagram which shows the structure of the inkjet printing apparatus which concerns on 1st Embodiment. It is a schematic block diagram of the conveyance part and printing part of the inkjet printing apparatus which concern on 1st Embodiment. It is explanatory drawing of the eccentric amount and head gap deviation | shift amount of a platen roller. It is a figure which shows an example of the eccentric amount of a platen roller. It is a figure which shows the other example of the eccentric amount of a platen roller. It is a figure which shows an example of head gap deviation | shift amount. FIG. 5 is an explanatory diagram of ink landing position deviation due to head gap deviation. FIG. 5 is an explanatory diagram of ink landing position deviation due to head gap deviation. It is a figure which shows an example of an ink landing time shift amount. It is a figure which shows an example of the amount of ink landing position deviation. It is a block diagram which shows the structure of the inkjet printing apparatus which concerns on 2nd Embodiment. It is a schematic block diagram of the conveyance part and printing part of the inkjet printing apparatus which concern on 2nd Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. Throughout the drawings, the same or equivalent parts and components are denoted by the same or equivalent reference numerals.

  The following embodiments exemplify devices for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, arrangement, etc. of each component. Is not specified as follows. The technical idea of the present invention can be variously modified within the scope of the claims.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of the ink jet printing apparatus according to the first embodiment of the present invention. FIG. 2 is a schematic configuration diagram of the conveyance unit and the printing unit of the inkjet printing apparatus shown in FIG. In the following description, the direction orthogonal to the paper surface of FIG. In addition, the top, bottom, left, and right of the paper surface in FIG.

  As shown in FIG. 1, the inkjet printing apparatus 1 according to the first embodiment includes a transport unit 2, a printing unit 3, a storage unit 4, and a control unit 5.

  The transport unit 2 continuously transports a web (corresponding to a print medium in claims) W. The web W is a band-shaped member made of paper, film, metal foil, or the like. The conveyance unit 2 includes a delivery unit 11, support rollers 12 and 13, a dancer roller 14, a guide roller 15, five platen rollers 16, and four timing belts (corresponding to connecting members in claims) 17. And a rotary encoder 18, guide rollers 19 and 20, and a winding unit 21.

  The sending unit 11 sends the web W from the web roll R. The web roll R is a roll of the web W. The delivery unit 11 includes a web roll support shaft 26 and a delivery motor 27.

  The web roll support shaft 26 rotatably supports the web roll R. The web roll support shaft 26 is formed in a long shape extending in the front-rear direction.

  The feed motor 27 rotates the web roll support shaft 26 clockwise in FIG. The web roll R rotates in the same direction by the rotation of the web roll support shaft 26, and the web W is sent out to the downstream side (right side).

  The support rollers 12 and 13 support the web W between the delivery unit 11 and the guide roller 15. The support rollers 12 and 13 are spaced apart from each other in the left-right direction between the delivery unit 11 and the guide roller 15 and are disposed at the same height.

  The dancer roller 14 pushes down the web W by its own weight between the support rollers 12 and 13. Thereby, the dancer roller 14 absorbs the slack of the web W. The dancer roller 14 moves up and down according to the amount of slack of the web W.

  The guide roller 15 guides the web W between the support roller 13 and the most upstream platen roller 16 in the web W conveyance direction.

  The platen roller 16 supports the web W and rotates following the web W below four inkjet heads 31 described later. The five platen rollers 16 are arranged so as to draw a convex arch. As a result, the web W is stretched between the platen rollers 16, and the web W is maintained in a stable posture.

  One platen roller 16 is disposed on the lower side of the web W, upstream of the uppermost inkjet head 31, between the inkjet heads, and downstream of the downstreammost inkjet head 31. In other words, one platen roller 16 is disposed on the upstream side and the downstream side of each inkjet head 31 on the opposite side of the inkjet head 31 across the web W.

  A pulley 28 is attached to the rotation axis of the platen roller 16. The pulley 28 spans the timing belt 17.

  The timing belt 17 rotates the platen roller 16 synchronously. Each timing belt 17 is stretched between pulleys 28 of a pair of adjacent platen rollers 16. As a result, all the platen rollers 16 are connected via the timing belt 17 to rotate synchronously.

  The rotary encoder 18 outputs a pulse signal for each predetermined rotation angle of the platen roller 16. The rotary encoder 18 is attached to the most upstream platen roller 16. The rotary encoder 18 may be attached to another platen roller 16.

  The guide rollers 19 and 20 guide the web W between the most downstream platen roller 16 and the winding unit 21.

  The winding unit 21 winds the printed web W. The winding unit 21 includes a winding shaft 29 and a winding motor 30.

  The winding shaft 29 winds and holds the web W. The winding shaft 29 is formed in a long shape extending in the front-rear direction.

  The winding motor 30 rotates the winding shaft 29 in the clockwise direction in FIG. The web W is wound around the winding shaft 29 by the rotation of the winding shaft 29.

  The printing unit 3 prints on the web W conveyed by the conveyance unit 2. The printing unit 3 includes four inkjet heads 31. The four inkjet heads 31 are disposed between the two adjacent platen rollers 16 above the platen roller 16.

  The inkjet head 31 has a plurality of nozzles 32 (see FIG. 3) arranged in the front-rear direction (main scanning direction) orthogonal to the web W conveyance direction, and ejects ink from the nozzles 32. The nozzle 32 opens on the ink discharge surface 31 a of the inkjet head 31. The ink discharge surface 31 a is a surface facing the web W of the inkjet head 31.

  The storage unit 4 stores ink landing time shift profile data (corresponding to profile data in claims) corresponding to each inkjet head 31. The storage unit 4 includes an HDD (Hard Disk Drive) or the like. The ink landing time shift profile data includes the amount of eccentricity for each predetermined rotation angle of the pair of platen rollers 16 corresponding to the ink jet head 31 and between the platen roller 16 and the ink jet head 31 in the web W conveyance direction. It is data indicating the amount of landing time deviation of ink according to the distance. Details of the ink landing time shift profile data will be described later.

  The control unit 5 controls the operation of the entire inkjet printing apparatus 1. The control unit 5 includes a CPU, a RAM, a ROM, and the like.

  When printing, the control unit 5 causes the ink jet head 31 to eject ink and print the web W while the web W is being transported by the transport unit 2. At this time, the control unit 5 controls the ink ejection timing in the inkjet head 31 using the ink landing time shift profile data.

  Next, the ink landing time shift profile data will be described.

  The ink landing time shift profile data is data used for controlling the ink discharge timing for suppressing the landing position shift of the ink due to the fluctuation of the head gap G caused by the eccentricity of the platen roller 16.

  As shown in FIG. 3, the head gap G is the distance between the ink ejection surface 31 a of the inkjet head 31 and the web W in the head height direction. More specifically, the head gap G is the distance between the opening of the nozzle 32 on the ink ejection surface 31a and the web W in the head height direction. Here, the head height direction is a direction orthogonal to the web W between the platen rollers 16 in an ideal case where the platen roller 16 has no eccentricity (web W indicated by a two-dot chain line in FIG. 3).

  It is the eccentricity of the pair of platen rollers 16 corresponding to each inkjet head 31 that affects the head gap G in each inkjet head 31. The pair of platen rollers 16 corresponding to the inkjet head 31 is a pair of platen rollers 16 including an upstream platen roller 16 and a downstream platen roller 16 that sandwich the inkjet head 31.

  As shown in FIG. 3, when the eccentric amount of the upstream platen roller 16 in the head height direction is δu, the eccentric amount δu is determined by the rotation center Cru of the upstream platen roller 16 and the platen roller 16. This is the amount of deviation in the head height direction from the center Cdu of the outer circumference circle. Similarly, when the eccentric amount of the downstream platen roller 16 in the head height direction is δd, the eccentric amount δd is the center of rotation of the downstream platen roller 16 and the center of the outer circumference of the platen roller 16. This is a deviation in the head height direction from Cdd.

  As shown in FIG. 3, the eccentric amount δu of the upstream platen roller 16 is ideal in that the platen roller 16 has no eccentricity at the height of the web W at the position of the rotation center Cru in the conveyance direction of the web W. This corresponds to a fluctuation amount with respect to the height of the web W in such a case. Similarly, the eccentric amount δd of the platen roller 16 on the downstream side is the height of the web W at the position of the rotation center Crd in the conveyance direction of the web W, and the web in an ideal case where the platen roller 16 is not eccentric. This corresponds to the amount of variation with respect to the height of W. Here, in FIG. 3, the platen roller 16 having no eccentricity is indicated by a two-dot chain line.

  As described above, the height of the web W fluctuates at the position of the platen roller 16 due to the eccentricity of the platen roller 16, so that the head gap G deviates from the ideal head gap Gi. The ideal head gap Gi is a designed head gap, and is an ideal head gap in which the platen roller 16 has no eccentricity.

  When the head gap deviation amount, which is the deviation amount of the head gap G with respect to the ideal head gap Gi, is δG, the head gap deviation amount δG is expressed by the following equation (1).

δG = (Ld × δu + Lu × δd) / (Lu + Ld) (1)
Here, Lu is a distance between the upstream platen roller 16 and the inkjet head 31 in the conveyance direction of the web W. Ld is the distance between the inkjet head 31 and the downstream platen roller 16 in the web W conveyance direction. More specifically, Lu is the distance between the rotation center Cru of the upstream platen roller 16 in the web W conveyance direction and the position of the nozzle 32 of the inkjet head 31. Ld is a distance between the position of the nozzle 32 of the inkjet head 31 and the rotation center Crd of the platen roller 16 on the downstream side in the conveyance direction of the web W.

  The eccentric amounts δu and δd of the platen roller 16 vary as the platen roller 16 rotates. Accordingly, the head gap G and the head gap deviation amount δG vary. For example, the eccentric amounts δu and δd vary as shown in FIGS. 4 and 5 according to the rotation angle of the platen roller 16 (the number of output pulses of the rotary encoder 18), and the head gap deviation amount δG as shown in FIG. fluctuate.

  When the head gap G deviates from the ideal head gap Gi, a deviation in ink landing time and a deviation in landing position occur. For example, as illustrated in FIG. 7, it is assumed that the ink 36 is ejected at a timing at which ink is landed on a target landing position P on the web W in a state where the head gap G is wider than the ideal head gap Gi. In this case, since the head gap G is wider than the ideal head gap Gi, the time from the ejection of the ink 36 to the landing on the web W is longer than when the head gap G is the ideal head gap Gi. Then, as shown in FIG. 8, the ink 36 lands at a position that is shifted upstream from the target landing position P. In FIG. 7 and FIG. 8, for easy understanding, the web W when the head gap G widens is drawn in parallel with the web W when the head gap G is the ideal head gap Gi.

  The ink landing time deviation amount Δt, which is the deviation amount of the time from when ink is ejected to landing on the web W to the time when the head gap G is the ideal head gap Gi, is expressed by the following equation (2). expressed.

Δt = δG / Vi (2)
Here, Vi is an ink discharge speed.

  The ink landing time deviation amount Δt varies as shown in FIG. 9 according to the head gap deviation amount δG which varies as shown in FIG. 6, for example.

  The ink landing position deviation amount Δy, which is the deviation amount of the ink landing position from the target landing position, is expressed by the following equation (3).

Δy = Δt × Vp (3)
Here, Vp is the conveyance speed of the web W.

  The ink landing position deviation amount Δy appears as shown in FIG. 10, for example, according to the ink landing time deviation amount Δt as shown in FIG.

  On the other hand, if the ink ejection timing is corrected according to the ink landing time deviation amount Δt, the deviation of the ink landing position can be suppressed. Therefore, the ink jet printing apparatus 1 stores data indicating the ink landing time deviation amount Δt for each predetermined rotation angle of the platen roller 16 (for each output pulse of the rotary encoder 18) as shown in FIG. This data is ink landing time shift profile data. In the inkjet printing apparatus 1, ink landing time shift profile data corresponding to each inkjet head 31 is stored in the storage unit 4.

  The ink landing time shift profile data is generated in advance and stored in the storage unit 4. The ink landing time shift profile data is generated as follows.

  First, the amount of eccentricity of each platen roller 16 in the head height direction is measured by a laser displacement meter or the like. The eccentric amount of each platen roller 16 is measured for each output pulse of the rotary encoder 18 with reference to the Z-phase signal of the rotary encoder 18. As a result, data as shown in FIGS. 4 and 5 indicating the eccentricity amount for each predetermined rotation angle of each platen roller 16 (for each output pulse of the rotary encoder 18) is generated.

  Next, FIG. 6 shows the head gap deviation amount δG for each predetermined rotation angle of the platen roller 16 corresponding to each ink jet head 31 according to the equation (1) using data indicating the eccentricity amount of each platen roller 16. Is generated.

  Next, using the data indicating the head gap deviation amount δG, the ink landing time deviation amount Δt for each predetermined rotation angle of the platen roller 16 corresponding to each ink-jet head 31 is expressed as shown in FIG. Data is generated. This data indicates the ink landing time deviation amount Δt corresponding to the number of pulses from the Z-phase signal with reference to the Z-phase signal of the rotary encoder 18. Data indicating the ink landing time shift amount Δt is stored in the storage unit 4 as ink landing time shift profile data.

  Next, the operation of the inkjet printing apparatus 1 will be described.

  When a print job is input, the control unit 5 activates the feed motor 27 and the take-up motor 30. Thereby, the web W starts to be continuously conveyed between the feeding unit 11 and the winding unit 21.

  When the conveyance of the web W is started, the support rollers 12 and 13, the dancer roller 14, the guide roller 15, each platen roller 16, and the guide rollers 19 and 20 are rotated by the web W. Since each platen roller 16 is connected via a timing belt 17, it rotates synchronously.

  After the conveyance speed of the web W reaches a predetermined speed, the control unit 5 controls each inkjet head 31 based on the print job to discharge ink while maintaining the conveyance speed. Thereby, an image is printed on the web W.

  At this time, the control unit 5 corrects the ink ejection timing in each inkjet head 31 using the ink landing time shift profile data corresponding to each inkjet head 31. Specifically, the control unit 5 acquires the value of the ink landing time shift amount Δt corresponding to the number of pulses from the Z-phase signal of the rotary encoder 18 from the ink landing time shift profile data. Then, the control unit 5 performs control so that the ink ejection timing is advanced or delayed by the value of the ink landing time deviation amount Δt during ink ejection.

  When printing is completed, the control unit 5 stops the feed motor 27 and the take-up motor 30. Thereby, conveyance of the web W stops and a series of operation | movement is complete | finished.

  As described above, in the inkjet printing apparatus 1, the storage unit 4 stores ink landing time shift profile data. The ink landing time shift profile data includes the eccentric amounts δu and δd for each predetermined rotation angle of the pair of platen rollers 16 corresponding to the ink jet head 31 and the platen roller 16 and the ink jet head 31 in the web W conveyance direction. The ink landing time deviation amount Δt according to the distances Lu and Ld between the two. The control unit 5 controls the ink ejection timing in the inkjet head 31 using the ink landing time shift profile data.

  Thereby, regardless of where the inkjet head 31 is disposed between the pair of platen rollers 16, it is possible to suppress the landing position deviation of the ink due to the fluctuation of the head gap G caused by the eccentricity of the platen roller 16. As a result, it is possible to reduce the deterioration in print image quality while reducing the restrictions on the layout of the inkjet head 31.

  Note that the platen roller 16 on the downstream side of the pair of platen rollers 16 corresponding to the ink jet head 31 may be configured to have a larger outer diameter than the platen roller 16 on the upstream side. That is, the five platen rollers 16 may be configured such that the outer diameter increases toward the downstream side.

  In this case, in the pair of platen rollers 16 corresponding to the inkjet head 31, the downstream platen roller 16 has a higher speed at the contact portion with the web W than the upstream platen roller 16. Thereby, generation | occurrence | production of the fluttering by the tension | tensile_strength fall of the web W is suppressed. As a result, it is possible to further reduce the decrease in print image quality.

(Second Embodiment)
FIG. 11 is a block diagram illustrating a configuration of the inkjet printing apparatus according to the second embodiment. FIG. 12 is a schematic configuration diagram of the conveyance unit and the printing unit of the inkjet printing apparatus shown in FIG.

  As shown in FIGS. 11 and 12, the inkjet printing apparatus 1A according to the second embodiment has a configuration in which the conveyance unit 2 of the inkjet printing apparatus 1 according to the first embodiment described above is replaced with a conveyance unit 2A.

  The transport unit 2A omits the pulley 28 and the timing belt 17 of the transport unit 2 in the above-described first embodiment, and the rotary encoder 18 is attached to each platen roller 16 to which the rotary encoder 18 is not attached in the transport unit 2. It is a configuration.

  In the ink jet printing apparatus 1 </ b> A, the storage unit 4 stores roller profile data corresponding to each platen roller 16. The roller profile data is data indicating the amount of eccentricity for each predetermined rotation angle of the platen roller 16 in the head height direction (for each output pulse of the rotary encoder 18) as shown in FIGS.

  In the inkjet printing apparatus 1 </ b> A, during printing based on a print job, the control unit 5 corrects the ink ejection timing in each inkjet head 31 using the roller profile data of each platen roller 16.

  Specifically, for each output pulse of each rotary encoder 18, the control unit 5 determines the amount of eccentricity δu of the upstream platen roller 16 corresponding to each inkjet head 31 and the downstream from the roller profile data of each platen roller 16. The eccentric amount δd of the platen roller 16 on the side is acquired. The control unit 5 calculates the head gap deviation amount δG by the above-described equation (1) using the acquired eccentricity amounts δu, δd and the distances Lu, Ld between the platen rollers 16 and the inkjet head 31. To do. Subsequently, the control unit 5 calculates the ink landing time deviation amount Δt by the above-described equation (2).

  For each rotation of the pair of platen rollers 16 corresponding to each inkjet head 31, the control unit 5 performs an ink landing time deviation amount Δt for each predetermined rotation angle (for each output pulse of the rotary encoder 18). Remember. Then, the control unit 5 performs control so that the ink ejection timing is advanced or delayed by the amount of the ink landing time deviation amount Δt stored before one rotation of the platen roller 16 during ink ejection.

  As described above, in the ink jet printing apparatus 1 </ b> A, the storage unit 4 stores the roller profile data of each platen roller 16. Based on the roller profile data of the pair of platen rollers 16 corresponding to the inkjet head 31 and the distances Lu and Ld between the platen roller 16 and the inkjet head 31 in the web W conveyance direction, the control unit 5 Ink discharge timing is controlled.

  Thereby, regardless of where the inkjet head 31 is disposed between the pair of platen rollers 16, it is possible to suppress the landing position deviation of the ink due to the fluctuation of the head gap G caused by the eccentricity of the platen roller 16. As a result, it is possible to reduce the deterioration in print image quality while reducing the restrictions on the layout of the inkjet head 31.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1,1A Inkjet printing apparatus 2,2A Conveying part 3 Printing part 4 Storage part 5 Control part 11 Sending part 12,13 Support roller 14 Dancer roller 15,19,20 Guide roller 16 Platen roller 17 Timing belt 18 Rotary encoder 21 Winding Part 31 Inkjet head W web

Claims (3)

An inkjet head that ejects ink onto a belt-like print medium that is continuously conveyed;
On the opposite side of the inkjet head across the print medium, a pair that is disposed on the upstream side and the downstream side of the inkjet head in the conveyance direction of the print medium, supports the conveyed print medium, and rotates following the print medium. Platen roller
A connecting member that synchronously rotates the pair of platen rollers;
Profile data showing the amount of landing time deviation of ink according to the amount of eccentricity for each predetermined rotation angle of the pair of platen rollers and the distance between each platen roller and the inkjet head in the conveyance direction of the print medium A storage unit for storing;
An inkjet printing apparatus comprising: a control unit that controls ink ejection timing in the inkjet head using the profile data.   2. The inkjet printing apparatus according to claim 1, wherein the platen roller on the downstream side of the pair of platen rollers has a larger outer diameter than the platen roller on the upstream side. An inkjet head that ejects ink onto a belt-like print medium that is continuously conveyed;
On the opposite side of the inkjet head across the print medium, a pair that is disposed on the upstream side and the downstream side of the inkjet head in the conveyance direction of the print medium, supports the conveyed print medium, and rotates following the print medium. Platen roller
A storage unit for storing data indicating the amount of eccentricity for each predetermined rotation angle of each of the platen rollers;
Control of ink ejection timing in the inkjet head based on the amount of eccentricity for each predetermined rotation angle of each platen roller and the distance between each platen roller and the inkjet head in the conveyance direction of the print medium An ink jet printing apparatus comprising: a control unit that performs: