JP2017149556A - Continuous paper sheet transport device and inkjet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transport a continuous paper sheet so that positional displacement does not occur at an image which is printed on the continuous paper sheet by an ink which is discharged from an injection head.SOLUTION: A guide roller unit which is constituted of a plurality of small-diameter rollers SR and a phase fixing mechanism LM is composed of an auxiliary roller 42 and an under-head guide roller 43 which bypass a transportation route of a continuous paper sheet W so as to elongate a contact length of the continuous paper sheet W with respect to an encoder roller 39 in a transportation direction of the continuous paper sheet W. The plurality of small-diameter rollers SR are aligned along the transportation route of the continuous paper sheet W in the auxiliary roller 42 and the under-head guide roller 43. Then, a rotation angle of each of the small-diameter rollers SR is relatively fixed by the phase fixing mechanism LM at a phase difference for reducing a change which occurs by the rotation angle of a rotation radius of a certain small-diameter roller SR in a contact position of the continuous paper sheet W more than a change of a transportation speed which occurs at the continuous paper sheet by contact with the other small-diameter roller SR.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an inkjet recording apparatus that performs printing while transporting a long continuous sheet as a printing medium.

  An ink jet recording apparatus that prints an image on a continuous sheet by ejecting ink from an ink jet head in accordance with the timing at which the continuous sheet that is being conveyed passes while conveying a continuous continuous sheet of paper generally called roll paper as a print medium It has been known.

  In this type of ink jet recording apparatus, the continuous paper being conveyed is brought into contact with the encoder roller provided in front of the ink jet head in the continuous paper carrying direction, and the encoder roller is rotated at a rotational speed synchronized with the continuous paper carrying speed. ing. And the timing which discharges ink from an inkjet head is determined based on the encoder pulse which an encoder roller outputs.

  For this reason, it is ideal to arrange the encoder roller immediately before the ink jet head so that the continuous paper that has passed through the encoder roller is fed directly to the ink jet head.

  On the other hand, in order to output an encoder pulse with a period synchronized with the continuous paper conveyance speed from the encoder roller, the length of the continuous paper contacting the encoder roller is increased, and the encoder roller is moved at the same speed as the continuous paper conveyance speed. Need to rotate.

  In view of this, a guide roller is provided before and after the encoder roller to largely reverse the conveyance direction of the continuous paper by the encoder roller. Therefore, the continuous paper that has passed through the encoder roller is fed into the inkjet head through the guide roller.

  Here, if there is a deviation in the accuracy of the guide roller, such as the roundness of the guide roller circumference or the guide roller rotating shaft being eccentric, the conveying speed of the continuous paper passing through the guide roller will be It changes with respect to the conveyance speed of the continuous paper at the time of passing.

  Then, since the conveyance speed of the continuous paper fed into the inkjet head is not synchronized with the cycle of the encoder pulse, even if ink is ejected from the inkjet head at the timing determined based on the encoder pulse, the image is positioned at the correct position on the continuous paper. It will not be printed.

  Therefore, when the printing position of the image on the recording medium is shifted due to a transport error due to the eccentricity of the rollers of the transport system, the amount of shift is measured from the test pattern printed on the recording medium, and the timing of ejecting ink from the inkjet head It is proposed to correct the image so that the image is printed at the correct position on the recording medium (for example, Patent Document 1). This proposal is for the case where a sheet is used as a recording medium, but it is conceivable to apply it when a continuous sheet is used as a recording medium.

JP 2008-260171 A

  However, if the proposal of Patent Document 1 is applied to a case where the recording medium is roll paper, that is, continuous paper, a test pattern is used to measure the amount of image printing positional deviation as in the case of sheet. After printing, it is necessary to further perform a procedure that is not in the case of a sheet, such as cutting continuous paper and setting it on a scanner.

  In addition, when the roller is replaced by maintenance regardless of the type of the recording medium, the correction amount of the ink ejection timing must be re-determined by performing the test pattern printing and the measurement of the printing position deviation amount again. Before that, in the first place, in order to determine the correction amount of the ejection timing, it takes time to print the test pattern and measure the printing position deviation amount.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to enable continuous paper to be transported so that an image printed on the continuous paper is not displaced by ink ejected from an inkjet head. There is to do.

In order to achieve the above object, a continuous paper conveyance device according to the first aspect of the present invention comprises:
An encoder roller that is rotated by contact with continuous paper (for example, continuous paper W in FIG. 1) fed into an ink jet head (for example, ink jet head 32 in FIG. 1) and outputs encoder pulses with a period corresponding to the rotation speed. For example, the encoder roller 39 and the encoder 40 in FIG.
A guide roller unit (e.g., a guide roller unit that is disposed on a conveyance path between the encoder roller and the inkjet head and rotates while guiding the continuous paper in contact with the continuous paper fed from the encoder roller to the inkjet head) Auxiliary roller 42 and head lower guide roller 43) of FIG.
In a continuous paper conveyance device (for example, the conveyance unit 31 in FIG. 1) having
The guide roller unit is
A plurality of rollers arranged side by side along the conveying path on the guide roller unit and individually rotated by contact with the continuous paper (for example, the small-diameter roller SR in FIG. 4);
A phase locking mechanism (for example, the phase locking mechanism LM in FIG. 4) that enables the rollers to rotate with a predetermined phase difference;
Have
The phase difference is caused by fluctuations in the conveyance speed that occur in the continuous paper that comes into contact with each roller due to changes in the rotation angle of the plurality of rollers (for example, FIGS. 6A to 6C and FIGS. c) fluctuations in the conveyance speed of the rollers A to C), the fluctuation range of the synthesized conveyance speed (for example, the fluctuation in the total conveyance speed in FIGS. 6D and 7D). ) Becomes the smallest (for example, the fluctuation of the total conveyance speed in FIG. 7D) (for example, the phase difference between the rotation angles determined between the two adjacent rollers (for example, FIG. (a) to (c) are the phase differences between the rollers A and B and the rollers B and C at the rotation angles indicated on the horizontal axis.

  Further, in the continuous paper conveyance device according to the second aspect of the present invention, the plurality of small diameter rollers are configured by a plurality of roller sets (for example, a roller set RS in FIG. 8) having at least two small diameter rollers. The phase fixing mechanism is provided for each roller set.

  Furthermore, the ink jet recording apparatus according to the third aspect of the present invention is configured to bring the continuous paper fed into the ink jet head into contact with an encoder roller, and based on the encoder pulse output from the encoder roller at a cycle corresponding to the rotation speed, 3. An ink jet recording apparatus (for example, the ink jet recording apparatus 1 in FIG. 1) that determines the timing at which ink is ejected from the ink jet head onto the continuous paper.

  According to the present invention, it is possible to transport the continuous paper so that the image printed on the continuous paper is not displaced by the ink ejected from the inkjet head.

  That is, when the guide roller bypasses the conveyance path of the continuous paper between the encoder roller and the inkjet head, the guide roller has a deviation in the roundness of the circumferential surface of the guide roller or the guide roller rotating shaft is eccentric. In some cases, the accuracy may be incorrect.

  When such a deviation in accuracy is present in the guide roller, the rotation radius of the guide roller at the contact position of the continuous paper periodically changes depending on the rotation angle of the guide roller, and the conveyance speed of the continuous paper passing through the guide roller is the encoder roller. It increases or decreases with respect to the conveyance speed of the continuous paper when it passes.

  Then, since the conveyance speed of the continuous paper fed into the inkjet head is not synchronized with the cycle of the encoder pulse, even if ink is ejected from the inkjet head at the timing determined based on the encoder pulse, the image is positioned at the correct position on the continuous paper. It will not be printed.

  Therefore, in the continuous paper conveying apparatus according to the first aspect of the present invention, the guide roller is formed as a unit, and the guide roller unit is configured by using a plurality of rollers arranged side by side. The guide roller unit is provided with a phase fixing mechanism so that each roller can rotate with a predetermined phase difference.

  Here, the predetermined phase difference means that the fluctuation width of the combined conveyance speed is the largest when the fluctuations of the conveyance speed respectively generated on the continuous paper in contact with each roller due to the change in the rotation angle of the plurality of rollers are combined. The phase difference of the rotation angle determined between two adjacent rollers is set to be smaller.

  When the phase fixing mechanism can rotate each roller with the phase difference determined in this way, even if the conveyance speed of the continuous paper contacting each roller fluctuates due to a change in the rotation angle of the roller, Variations in the conveyance speed generated on the continuous paper are attenuated by variations in the conveyance speed generated by other rollers. For this reason, as a whole of the guide roller unit, it is possible to make the conveyance speed of the continuous paper difficult to deviate from the conveyance speed of the continuous paper when the encoder roller passes.

  This makes it easy to synchronize the conveyance speed of the continuous paper fed into the inkjet head with the cycle of the encoder pulse, and positions the image on the continuous paper printed by the ink ejected from the inkjet head at a timing determined based on the encoder pulse. The continuous paper can be transported so that no deviation occurs.

  Further, according to the continuous paper conveyance device according to the second aspect of the present invention, the rollers that can be rotated by the phase fixing mechanism with a predetermined phase difference include at least two rollers constituting each roller set of the guide roller unit. It becomes a roller unit. For this reason, it is possible to reduce the fluctuation in the conveyance speed generated on the continuous paper due to the change in the rotation angle of the roller, rather than allowing all the rollers of the guide roller unit to rotate with a predetermined phase difference by one phase fixing mechanism. It is possible to easily determine the phase difference between the rotation angles of the rollers.

  The ink jet recording apparatus according to the third aspect of the present invention can obtain the same effects as those of the continuous paper conveying apparatus according to the first or second aspect of the present invention.

It is explanatory drawing which shows schematic structure of the inkjet recording device which concerns on one Embodiment of this invention. It is a perspective view which shows the guide roller arrange | positioned between an encoder roller and an inkjet head in a general inkjet recording device. (A), (b) is explanatory drawing which shows the conveyance speed change which arises in the continuous paper which contacted the roller when the roller of the roller set of FIG. 4 has eccentricity of a rotating shaft. FIG. 4 is an explanatory diagram conceptually showing each roller and a phase fixing mechanism in FIG. 3. FIG. 3 is a perspective view showing a guide roller unit disposed between an encoder roller and an ink jet head in the ink jet recording apparatus of FIG. 1 instead of the guide roller of FIG. 2. FIGS. 5A to 5C are graphs showing a change in the conveyance speed of a continuous sheet due to the rotation radius of the roller at the contact position of the continuous sheet being different depending on the rotation angle, and FIG. It is the graph which combined the change of the conveyance speed of the continuous paper in each small diameter roller of a)-(c). FIGS. 5A to 5C are graphs showing a change in the conveyance speed of a continuous sheet due to the rotation radius of the roller at the contact position of the continuous sheet being different depending on the rotation angle, and FIG. It is the graph which combined the change of the conveyance speed of the continuous paper in each small diameter roller of a)-(c). It is explanatory drawing which shows notionally the roller set in the guide roller unit of FIG.

  Hereinafter, an embodiment of the present invention will be described 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 embodiment exemplifies an apparatus or the like for embodying the technical idea of the present invention. The technical idea of the present invention is based on the material, shape, structure, arrangement, etc. of each component. It is not specified to the following. The technical idea of the present invention can be variously modified within the scope of the claims.

  FIG. 1 is an explanatory diagram showing a schematic configuration of an ink jet recording apparatus including a continuous paper conveyance device according to an embodiment of the present invention. In the following description, the direction orthogonal to the paper surface of FIG. 1 is the front-rear direction, and the front surface direction is the front. Also, the top, bottom, left, and right of the paper surface in FIG.

  As shown in FIG. 1, the ink jet recording apparatus 1 of this embodiment includes a delivery unit 2, a printer unit 3, a winding unit 4, and a control unit 5.

  The sending unit 2 sends a continuous paper W, which is a long print medium made of paper, film, or the like, to the printer unit 3. The delivery unit 2 includes a web roll support shaft 11, guide rollers 13 and 14, and an upstream buffer unit 15.

  The web roll support shaft 11 rotatably supports the web roll 16. The web roll support shaft 11 is formed in a long shape extending in the front-rear direction. The web roll 16 is a roll of continuous paper W.

  The web roll support shaft 11 is driven to rotate clockwise in FIG. 1 by a feed motor (not shown). The web roll 16 rotates in the same direction by the rotation of the web roll support shaft 11, and the continuous paper W is sent out to the downstream side (right side).

  The guide rollers 13 and 14 guide the continuous paper W between the web roll 16 and the upstream buffer unit 15.

  The upstream buffer unit 15 absorbs the slack of the continuous paper W between the guide roller 14 and a guide roller 36 of the printer unit 3 described later. The upstream buffer unit 15 includes support rollers 17 to 20 and dancer rollers 21 and 22.

  The support rollers 17 to 20 support the continuous paper W between the guide roller 14 and the guide roller 36. The support rollers 17 to 20 are arranged at the same height with an interval in the left-right direction.

  The dancer rollers 21 and 22 push down the continuous paper W by its own weight between the support rollers 17 and 18 and between the support rollers 18 and 19, respectively, and absorb the slack of the continuous paper W. The dancer rollers 21 and 22 move up and down according to the amount of sag of the continuous paper W.

  The printer unit 3 prints on the continuous paper W while conveying the continuous paper W. The printer unit 3 includes a tension applying unit 3a, an encoder unit 3b, and a printing unit 3c.

  The tension applying unit 3 a includes a guide roller 36, a pair of tension applying rollers 37, and a brake 38.

  The guide roller 36 guides the continuous paper W between the support roller 20 of the delivery unit 2 and the tension applying roller 37.

  The pair of tension applying rollers 37 applies tension to the continuous paper W. The pair of tension applying rollers 37 rotates following the continuous paper W conveyed by the pair of conveying rollers 48 while nipping the continuous paper W. When one of the tension applying rollers 37 is braked by the brake 38, tension is applied to the continuous paper W between the transport roller 48 and the tension applying roller 37.

  The brake 38 brakes one tension applying roller 37. The brake 38 is a powder brake, for example. The tension of the continuous paper W is adjusted according to the output of the brake 38.

  The encoder unit 3 b includes an encoder roller 39, an encoder 40, and auxiliary rollers 41 and 42.

  The encoder roller 39 is a roller on which the encoder 40 is installed. A continuous paper W is wound around the encoder roller 39. The encoder roller 39 rotates following the continuous paper W being conveyed.

  The encoder 40 outputs a pulse signal for each predetermined rotation angle of the encoder roller 39. The output pulse signal of the encoder 40 is used for controlling the ink ejection timing by the inkjet head 32. In the present embodiment, the encoder roller 39 and the encoder 40 constitute the encoder roller in the claims.

  The auxiliary rollers 41 and 42 assist the winding of the continuous paper W around the encoder roller 39. The auxiliary rollers 41 and 42 are spaced apart from each other in the left-right direction across the encoder roller 39 and are disposed below the encoder roller 39. The auxiliary rollers 41 and 42 hold the continuous paper W from above on the upstream side (left side) and the downstream side (right side) of the encoder roller 39, respectively.

  On the upstream side of the encoder roller 39, the auxiliary roller 41 contacts the upper left side of the peripheral surface of the encoder roller 39 with the continuous paper W fed from the pair of tension applying rollers 37, and the encoder roller 39 is not touched. It functions to increase the contact length of the continuous paper W in the conveyance direction of the continuous paper W.

  In addition, on the downstream side of the encoder roller 39, that is, between the encoder roller 39 and the inkjet head 32, the auxiliary roller 42 causes the continuous paper W that has contacted the upper left side of the encoder roller 39 to pass around the encoder roller 39. It functions to increase the contact length of the continuous paper W with respect to the encoder roller 39 in the conveying direction of the continuous paper W by contacting the upper right side of the surface.

  The printing unit 3 c includes four inkjet heads 32 and head lower guide rollers 43 to 46.

  The inkjet head 32 prints an image by ejecting ink onto the continuous paper W. The four inkjet heads 32 are arranged in parallel along the sub-scanning direction (left-right direction) that is the conveyance direction of the continuous paper W.

  The head lower guide rollers 43 to 46 guide the continuous paper W conveyed under the inkjet head 32. The head lower guide rollers 43 to 46 have a cylindrical shape elongated in the front-rear direction.

  The head lower guide roller 43 is provided on the downstream side of the auxiliary roller 42, and is disposed at a height at which an appropriate head gap is provided between the continuous paper W and the inkjet head 32. The continuous paper W is wound around the head lower guide roller 43 from the left, and the continuous paper W is fed horizontally to the right.

  The head lower guide roller 43 functions to guide the continuous paper W that is separated from the ink jet head 32 by a distance beyond the appropriate head gap by passing the auxiliary roller 42 to the position of the appropriate head gap.

  Therefore, in the present embodiment, the auxiliary roller 42 and the head lower guide roller 43 have the contact length of the continuous paper W with respect to the encoder roller 39 between the encoder roller 39 and the inkjet head 32, and convey the continuous paper W. This corresponds to a guide roller that bypasses the conveyance path of the continuous paper W so as to increase in the direction.

  The pair of head lower guide rollers 44 and 45 are arranged side by side on the downstream side of the inkjet head 32, and the lower head lower guide roller 45 is arranged at the same height as the head lower guide roller 43. . Ink is ejected from the inkjet head 32 onto the continuous paper W between the head lower guide rollers 43 and 45 for printing.

  The head lower guide roller 46 is disposed on the lower left side of the head lower guide roller 45. The pair of head lower guide rollers 44 and 45 nips the continuous paper W on which an image (not shown) is printed by the ink ejected from the inkjet head 32 and sends it to the left. A continuous paper W is wound around the head lower guide roller 46 from the left.

  The winding unit 4 winds the continuous paper W printed by the printer unit 3. The winding unit 4 includes a pair of conveying rollers 48, a guide roller 56, a downstream buffer unit 57, a guide roller 58, and a winding shaft 59.

  The pair of transport rollers 48 transport the continuous paper W fed from the head lower guide roller 46 toward the winding unit 4. The conveyance roller 48 is disposed on the downstream side of the head lower guide roller 46 and conveys the continuous paper W while nipping. The transport roller 48 is rotationally driven by a transport motor (not shown).

  The guide roller 56 guides the continuous paper W between the conveyance roller 48 of the printer unit 3 and the downstream buffer unit 57.

  The downstream buffer unit 57 absorbs the slack of the continuous paper W between the guide roller 56 and the guide roller 58. The downstream buffer unit 57 includes support rollers 61 to 63 and dancer rollers 64 and 65.

  The support rollers 61 to 63 support the continuous paper W between the guide roller 56 and the guide roller 58. The support rollers 61 to 63 are arranged at the same height with an interval in the left-right direction.

  The dancer rollers 64 and 65 push down the continuous paper W by its own weight between the support rollers 61 and 62 and between the support rollers 62 and 63, respectively, and absorb the slack of the continuous paper W. The dancer rollers 64 and 65 move up and down according to the amount of sag of the continuous paper W.

  The guide roller 58 guides the continuous paper W between the downstream buffer portion 57 and the take-up shaft 59.

  The take-up shaft 59 takes up and holds the continuous paper W. The winding shaft 59 is formed in a long shape extending in the front-rear direction.

  The winding shaft 59 is driven to rotate clockwise in FIG. 1 by a winding motor (not shown). The continuous paper W is wound around the winding shaft 59 by the rotation of the winding shaft 59.

  Of the printer unit 3 and the winding unit 4 described above, the transport unit 31 for the continuous paper W is configured by the portion of the printer unit 3 excluding the inkjet head 32. The transport unit 31 transports the continuous paper W transported from the delivery unit 2. The transport unit 31 constitutes a continuous paper transport device.

  The control unit 5 controls the operation of each unit of the inkjet recording apparatus 1. The control unit 5 includes a CPU, a RAM, a ROM, a hard disk, and the like.

  Next, specific configurations of the auxiliary roller 42 and the head lower guide roller 43 provided in the printing unit 3c of the printer unit 3 will be described. The auxiliary roller 42 and the head lower guide roller 43 are continuous paper W between the encoder roller 39 and the inkjet head 32 so as to increase the contact length of the continuous paper W with the encoder roller 39 in the transport direction of the continuous paper W. It functions as a guide roller that bypasses the conveyance path.

  In a general ink jet recording apparatus, the auxiliary roller 42 and the head lower guide roller 43 are constituted by a single roller R as shown in the perspective view of FIG. When this single roller R bypasses the conveyance path of the continuous paper W between the encoder roller 39 and the inkjet head 32 so as to increase the contact length with the encoder roller 39, the peripheral surface of the roller R The accuracy of the roller R may be out of order, for example, the roundness of the roller may be out of order or the rotational axis of the roller R is eccentric.

  When such a deviation in accuracy is present in the roller R, the rotation radius r of the roller R at the contact position of the continuous paper W depends on the rotation angle of the roller R as shown in the explanatory diagrams of FIGS. Instead, the conveyance speed of the continuous paper W passing through the roller R is increased or decreased with respect to the conveyance speed of the continuous paper W when passing through the encoder roller 39 according to the rotation angle of the roller R.

  Then, since the conveyance speed of the continuous paper W fed into the inkjet head 32 is not synchronized with the cycle of the encoder pulse output from the encoder 40, ink is ejected from the inkjet head 32 to the continuous paper W at a timing determined based on the encoder pulse. Even if this is done, an image (not shown) will not be printed at the correct position on the continuous paper W.

  Therefore, in the inkjet recording apparatus 1 of the present embodiment, the auxiliary roller 42 and the head lower guide roller 43 corresponding to the guide roller that bypasses the conveyance path of the continuous paper W between the encoder roller 39 and the inkjet head 32 are unitized. As shown in the explanatory diagram of FIG. 4, the guide roller unit includes a plurality of small diameter rollers SR and a phase fixing mechanism LM.

  Specifically, the rotation angle of a plurality of small-diameter rollers SR arranged along the conveyance path of the continuous paper W in the auxiliary roller 42 and the head lower guide roller 43 is relatively fixed by the phase fixing mechanism LM.

  The phase locking mechanism LM is, for example, a single unit whose center of rotation is the center of curvature of an arc that meshes with a gear (not shown) connected to the rotation shaft of each small-diameter roller SR and passes through the rotation center of each small-diameter roller SR. It can be configured with a gear for interlocking. Thereby, each small diameter roller SR can be rotated synchronously in the same direction. Further, the phase fixing mechanism LM may be configured by reducing the diameter of the interlocking gear and interposing a transmission gear (or gear train) between the gear of each small-diameter roller SR and the interlocking gear.

  In the guide roller unit constituting the auxiliary roller 42 and the head lower guide roller 43, the continuous paper W is in contact with each small diameter roller SR from the outside as shown in the perspective view of FIG. It is conveyed downstream at the rotational speed at the contact location.

  Here, when the auxiliary roller 42 and the head lower guide roller 43 are constituted by a guide roller unit and a plurality of small-diameter rollers SR are used, the accuracy of the rollers does not become inaccurate. In other words, each small-diameter roller SR may have an accuracy error such as a deviation in the roundness of the peripheral surface or an eccentric eccentricity of the rotating shaft.

  For example, it is assumed that the accuracy of the three small-diameter rollers SR constituting the guide roller unit is incorrect, and the rotation radius of the small-diameter roller SR at the contact position of the continuous paper W varies depending on the rotation angle of the small-diameter roller SR.

  When the rotation radius of the small-diameter roller SR at the contact position of the continuous paper W changes, the moving speed of the peripheral surface of the small-diameter roller SR at that position changes, as shown in the graphs of FIGS. The conveyance speed of the continuous paper W in contact with the small diameter roller SR also changes. Specifically, if the rotation radius of the small diameter roller SR at the contact position of the continuous paper W is longer than usual, the conveyance speed of the continuous paper W becomes faster than usual, and the rotation radius of the small diameter roller SR at the contact position of the continuous paper W Is shorter than usual, the conveyance speed of the continuous paper W becomes slower than usual.

  Depending on the combination of the phase differences of the rotation angles of the three small-diameter rollers SR, when the continuous paper W is in contact with the circumferential surface position where the rotation radius of a certain small-diameter roller SR is long, the continuous paper W There is a possibility that the small-diameter roller SR may simultaneously contact a circumferential surface position having a long turning radius. In this case, the increase in the conveyance speed of the continuous paper W at the contact points with the plurality of small-diameter rollers SR is accumulated, and the conveyance speed of the continuous paper W greatly deviates from the normal speed.

  The same is true when a continuous paper W is in contact with a circumferential surface position where a rotation radius of a small-diameter roller SR is short, and the continuous paper W simultaneously contacts a circumferential surface position where the rotation radius of another small-diameter roller SR is short. This also occurs when the decrease in the conveyance speed of the continuous paper W at the contact points with the plurality of small diameter rollers SR is accumulated. The graph of FIG. 6D shows a case where the increase or decrease in the conveyance speed of the continuous paper W at the contact point with each small diameter roller SR is accumulated by the combination of the phase differences of the rotation angles of the small diameter rollers SR. ing.

  Therefore, in the present embodiment, a change in the conveyance speed that occurs in the continuous paper W that comes into contact with the small-diameter roller SR due to a change in the rotation angle of a certain small-diameter roller SR is continuously detected in the other small-diameter rollers SR. Each small-diameter roller SR can be rotated by the phase fixing mechanism LM with a phase difference that is reduced by fluctuations in the conveyance speed generated on the paper W.

  Specifically, this phase difference is combined when the fluctuations in the conveyance speed respectively generated on the continuous paper W in contact with each small diameter roller SR due to the change in the rotation angle of each small diameter roller SR constituting the guide roller unit is combined. This is the phase difference of the rotation angle determined between the two adjacent small-diameter rollers SR so that the fluctuation range of the transport speed is minimized.

  Therefore, for example, when the three small diameter rollers SR of A to C constitute the guide roller unit, the phase difference of the rotation angle is determined between the small diameter roller SR of A and the small diameter roller SR of B, and The phase difference of the rotation angle is determined between the small diameter roller SR of B and the small diameter roller SR of C.

  Here, the graphs of FIGS. 6A to 6C show the fluctuations in the conveyance speed respectively generated in the continuous paper W due to the change in the rotation angle of each small-diameter roller SR. In the graphs of FIGS. 6A to 6C, the phase difference of the rotation angle between the A small-diameter roller SR and the B small-diameter roller SR is 0 °, and the B small-diameter roller SR. The phase difference of the rotation angle between the small diameter roller SR and the small diameter roller SR is also 0 °.

  As described above, when the phase difference between the rotation angles of the small diameter rollers SR of A and B and between the small diameter rollers SR of B and C is 0 °, the continuous paper W is conveyed by the change of the rotation angle of each small diameter roller SR. By synthesizing the fluctuations that occur in the speed, the conveyance speed of the continuous paper W that passes through the guide roller unit fluctuates with a large fluctuation width as shown in the graph of FIG. Therefore, in order to reduce the fluctuation range of the conveyance speed, the phase difference of the rotation angle is changed between one or both of the small diameter rollers SR of A and B and the small diameter rollers SR of B and C.

  For example, if the phase difference of the rotation angle between the small diameter rollers SR of A and B remains 0 ° and the phase difference of the rotation angle between the small diameter rollers SR of B and C is changed from 0 ° to 180 °, the small diameter of C The conveyance speed of the continuous paper W that has fluctuated in the cycle shown in the graph of FIG. 6C due to the change in the rotation angle of the roller SR changes in the cycle shown in the graph of FIG.

  Then, fluctuations that occur in the conveyance speed of the continuous paper W that is in contact with each of the small-diameter rollers SR due to the rotation angles of the two small-diameter rollers SR A and B are caused to the small-diameter roller SR by the rotation angle of the small-diameter roller SR of C. It is reduced by fluctuations that occur in the conveyance speed of the continuous paper W that comes into contact. As a result, when the fluctuations that occur in the conveyance speed of the continuous paper W in contact with the small diameter rollers SR due to the change in the rotation angle of the three small diameter rollers SR of A to C are combined, the fluctuation width becomes the smallest.

  Therefore, the three small-diameter rollers SR are maintained with such a phase difference that the conveying speed of the continuous paper W contacting the small-diameter rollers SR changes as shown in the graphs of FIGS. In this state, each small-diameter roller SR is rotated by the phase fixing mechanism LM. As a result, as shown in the graph of FIG. 7D, the fluctuation amount of the conveyance speed obtained by synthesizing the change in the conveyance speed of the continuous paper W at the contact position with each small-diameter roller SR is determined as the contact position with each small-diameter roller SR. , The amount of change in the conveyance speed that occurs in the continuous paper W can be made smaller.

  Thus, in the inkjet recording apparatus 1 of the present embodiment, the phase difference between the rotation angles of the plurality of small-diameter rollers SR is determined in advance as described above, and the phase fixing mechanism is maintained while maintaining the phase difference. The auxiliary roller 42 and the head lower guide roller 43 disposed between the encoder roller 39 and the ink jet head 32 are configured by a guide roller unit that can rotate each small-diameter roller SR by LM.

  For this reason, by providing an appropriate phase difference between the rotation angles of the small diameter rollers SR by the phase fixing mechanism LM, the conveyance speed when the encoder roller 39 passes through the continuous paper W passing through the small diameter rollers SR. Can be offset or reduced by a change in the conveyance speed that occurs when the continuous paper W passes through the other small-diameter rollers SR.

  Therefore, even if the accuracy of each small-diameter roller SR constituting the guide roller unit is inaccurate, as a whole of the guide roller unit, the transport speed of the continuous paper W during the passage of the encoder roller 39 is set as the transport speed of the continuous paper W. On the other hand, it can be made difficult to shift.

  Therefore, it is easy to synchronize the conveyance speed of the continuous paper W fed into the inkjet head 32 with the cycle of the encoder pulse, and the correct position of the continuous paper W is determined by the ink ejected from the inkjet head 32 at a timing determined based on the encoder pulse. The continuous paper W can be conveyed so that the image is printed without any positional deviation.

  A plurality of small diameter rollers SR may be divided into several roller sets, and each roller set may be constituted by at least two adjacent small diameter rollers SR. In the example shown in the explanatory diagram of FIG. 8, one roller set RS is configured by three small diameter rollers SR of A to C adjacent to each other.

  In this case, in each roller set RS, the fluctuation range of the conveyance speed of the synthesized word obtained by synthesizing the fluctuation of the conveyance speed of the continuous paper W generated in each of the plurality of small diameter rollers SR constituting the roller set RS is minimized. Furthermore, the phase difference of the rotation angle of each small-diameter roller SR is determined in advance for each roller set RS. Then, each small-diameter roller SR of the roller set RS can be rotated by the phase fixing mechanism LM while maintaining the determined phase difference.

  With this configuration, the variation in the conveyance speed of the continuous paper W caused by the change in the rotation angle of a certain small-diameter roller SR is reduced by the fluctuation in the conveyance speed of the continuous paper W caused by the change in the rotation angle of another small-diameter roller SR. Thus, the number of phase differences that minimize the combined fluctuation range obtained by combining the fluctuations in the conveyance speed of the continuous paper W generated by all the small diameter rollers SR is smaller than that of the small diameter rollers SR constituting the guide roller unit. What is necessary is just to find between each small diameter roller SR which comprises roller set RS.

  For this reason, continuous paper is produced by fluctuations in the rotation angle of each small-diameter roller SR, rather than allowing the rotation angles of all the small-diameter rollers SR constituting the guide roller unit to be rotated with a phase difference determined in advance by one phase fixing mechanism LM. It is possible to easily determine the phase difference between the rotation angles of the small-diameter rollers SR that minimizes the combined fluctuation range obtained by combining the fluctuations in the conveyance speed generated in W.

  Further, 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. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiment.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Sending part 3 Printer part 3a Tension providing part 3b Encoder part 3c Printing part 4 Winding part 5 Control part 11 Web roll support shaft 13, 14 Guide roller 15 Upstream buffer part 16 Web roll 17-20, 61 ˜63 Support rollers 21, 22, 64, 65 Dancer roller 31 Conveying section 32 Inkjet head 36, 56, 58 Guide roller 37 Tension applying roller 38 Brake 39 Encoder roller (encoder roller)
40 Encoder (Encoder Roller)
41 Auxiliary roller 42 Auxiliary roller (guide roller unit)
43 Head lower guide roller (guide roller unit)
44 to 46 Head lower guide roller 48 Conveying roller 57 Downstream buffer section 59 Winding shaft LM Phase fixing mechanism R roller RS roller set r Roller rotation radius SR Small diameter roller W Continuous paper

Claims (3)

An encoder roller that is rotated by contact with continuous paper fed into the inkjet head and outputs encoder pulses with a period according to the rotation speed;
A guide roller unit that is disposed on a transport path between the encoder roller and the inkjet head, and rotates while guiding the continuous paper in contact with the continuous paper fed from the encoder roller to the inkjet head;
In a continuous paper transport device having
The guide roller unit is
A plurality of rollers arranged side by side along a conveying path on the guide roller unit, and individually rotated by contact with the continuous paper;
A phase fixing mechanism that allows the rollers to rotate with a predetermined phase difference;
Have
The phase difference is such that the fluctuation width of the combined conveyance speed becomes the smallest when the fluctuations of the conveyance speed respectively generated in the continuous paper contacting with each roller due to the change in the rotation angle of the plurality of rollers are combined. , The phase difference of the rotation angle respectively determined between two adjacent rollers.
Continuous paper transport device.   2. The continuous paper conveyance device according to claim 1, wherein the plurality of rollers includes a plurality of roller sets including at least two of the rollers, and the phase fixing mechanism is provided for each of the roller sets. The continuous paper fed into the ink jet head is brought into contact with the encoder roller, and the timing for ejecting ink from the ink jet head onto the continuous paper is determined based on the encoder pulse output from the encoder roller at a cycle corresponding to the rotation speed. In an inkjet recording apparatus,
It has the continuous paper conveyance apparatus of Claim 1 or 2.
Inkjet recording device.

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