JP2013006644A - Recording medium conveyance device and recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a recorded image high in the conveyance accuracy of a recording medium in a short time.SOLUTION: A recording medium conveyance device includes: a conveyance means for conveying the recording medium that is withdrawn from roll paper as a specific length unit of the paper; a rotation load means for applying a force to the recording medium in a direction opposite to its conveyance direction; and a determination means for determining that the force is applied to the recording medium in the opposite direction to the conveyance direction. When the force is not applied to the recording medium in the opposite direction to the conveyance direction while the recording medium is conveyed based on the specific length, the determination means corrects a conveyance amount of the specific length of the recording medium.

Description

  The present invention relates to a recording medium conveying apparatus and a recording apparatus, and more particularly to a recording medium conveying apparatus and a recording apparatus that perform conveyance amount correction.

  The recording apparatus records the recording medium while conveying the recording medium by a predetermined amount, and various proposals have been made for the recording medium conveying method and the control means due to the increasing demand for higher image quality. For example, in order to correct skewing and meandering during the conveyance of the recording medium, a recording medium is conveyed while applying a force (back tension) to the conveyed recording medium in a direction opposite to the conveying direction. ing. In such a recording medium, in consideration of the state in which the back tension is always applied, the conveyance correction amount in one pass is determined for each type of recording medium, for each width size, for each recording mode (conveyance amount), and for the recording medium. High-accuracy conveyance is performed for each winding diameter.

  However, in the conveyance control of the roll-shaped recording medium in a state where such back tension is applied, the conveyance load fluctuates due to the inertia due to the rotation of the roll paper around which the recording medium is wound in a roll shape. For example, roll paper may be sent out in the transport direction beyond the transport amount due to the inertia of the roll paper during transport, the transport amount in one pass, and acceleration / deceleration during transport. At this time, the roll paper rotates in the conveyance direction, and rotates in the rewinding direction when the accompanying force disappears. When transport for the next one pass is performed in a state in which the follow-up state occurs irregularly, for example, back tension does not act on each transport, or it acts from the middle of one pass. And the back tension acting state becomes unstable. That is, the conveyance amount becomes unstable due to a different conveyance load variation for each pass. As a result, image deterioration is caused.

  For example, Japanese Patent Application Laid-Open No. 2004-228867 provides high accuracy by providing speed detection means upstream and downstream of the image forming unit, calculating a correction amount of the conveyance position deviation from the conveyance speed, and performing conveyance correction. A technique for carrying and suppressing image deterioration is disclosed.

JP 2002-236404 A

  However, in the technique disclosed in Patent Document 1, it is necessary to correct the transport amount by setting a value for correcting the transport amount after the recording medium is transported for one pass. Specifically, for each one-pass conveyance, the conveyance correction amount must be obtained by detecting the conveyance speed at an arbitrary point from the respective conveyance speeds based on the upstream and downstream speed detection means. Therefore, it takes a long time to obtain the conveyance amount, and the productivity may decrease.

  The present invention has been made in view of the above points, and an object thereof is to provide a recording medium transport apparatus and a recording apparatus that can obtain a recording image with high recording medium transport accuracy in a short time.

  In order to achieve the above object, the present invention applies a conveying means for conveying a recording medium drawn from roll paper in units of a predetermined length, and a force in a direction opposite to the conveying direction of the recording medium is applied to the recording medium. A recording medium conveying apparatus comprising: a rotational load means; and a judging means for judging that a force in the direction opposite to the conveying direction acting on the recording medium is not acting, wherein the recording medium conveying device has the predetermined length of the recording medium. During the conveyance, when the force in the direction opposite to the conveyance direction acting on the recording medium is not applied by the determination unit, the conveyance amount of the predetermined length of the recording medium is corrected.

  According to said structure, the back tension which acts on the recording medium conveyed can be judged for every pass, and conveyance amount can be adjusted. Thereby, it is possible to obtain a recorded image with high conveyance accuracy of the recording medium in a short time.

FIG. 3 is a schematic perspective view illustrating a sheet conveying device of the recording apparatus according to the first embodiment. FIG. 2 is a schematic longitudinal sectional view illustrating an exterior of the recording apparatus illustrated in FIG. 1. FIG. 3 is a schematic perspective view illustrating a main part of the sheet conveying apparatus according to the first embodiment. FIG. 6 is a schematic diagram illustrating a drive command for a conveyance motor of the sheet conveyance apparatus according to the first embodiment. It is a table | surface which shows the rotation detection threshold value of 1st Embodiment. It is a figure which shows the speed profile at the time of conveyance correction | amendment of 1st Embodiment. It is a table | surface which shows the conveyance correction amount of 1st Embodiment. It is a block diagram which shows the flow of the conveyance correction control in 1 pass of 1st Embodiment. It is a flowchart which shows the procedure of the conveyance correction | amendment of 1st Embodiment. It is a figure which shows the speed profile at the time of conveyance correction | amendment of 2nd Embodiment. It is a schematic diagram which shows the principal part structure of the sheet conveying apparatus of 3rd Embodiment. It is a figure which shows the speed profile at the time of the conveyance correction of 3rd Embodiment.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic perspective view illustrating a sheet conveying device of the recording apparatus according to the present embodiment. 2 is a schematic longitudinal sectional view showing the exterior of the recording apparatus shown in FIG. The recording apparatus 1 includes a roll paper feeding unit 10 for rotatably winding and holding a roll-shaped recording sheet Pr (hereinafter also referred to as roll paper) that is a recording medium of the present embodiment. Further, an LF conveyance unit 40 that conveys the image to the image forming unit 30 that records an image on the roll paper Pr, and a paper discharge unit 50 that discharges the sheet after image formation to the outside of the recording apparatus main body.

  FIG. 3 is a schematic perspective view showing a main part of the sheet conveying apparatus of the present embodiment. The sheet conveying apparatus of the present embodiment feeds and conveys a roll-shaped recording sheet Pr.

  First, the LF transport unit 40 and the roll paper feed unit 10 will be described.

  The conveying roller 41 conveys a predetermined amount of roll paper in a direction (Y direction, backward scanning direction) that intersects the scanning direction (X direction, main scanning direction) of the recording head 31. The conveyance roller 41 is driven by a conveyance motor 42 connected to one side end. The pinch roller 43 is rotatably held by the pinch roller arm 44, and is pressed against the transport roller 41 by a pinch roller spring (not shown) at the rear thereof to be rotated. A plurality of pinch rollers 43 are arranged in the main scanning direction. A transport pulley 46 is fixed to the shaft of the transport roller 41. The transport roller 41 is rotationally driven by being transmitted from the drive of the transport motor 42 to the transport pulley 46 via the transport belt 45. When the roll paper Pr is rewound, a rotation speed difference that is slower than that of the rewind motor 11 is provided, and the roll paper Pr rotates in the direction opposite to the transport direction.

  The roll paper feeding unit 10 has flanges 12L and 12R (not shown) on both sides, and the roll paper Pr is wound with the flanges 12L and 12R (not shown) regulating the position in the width direction of the recording sheet. It has been turned. Both ends of the roll paper feeding unit 10 are rotatably supported by bearings 13L and 13R (not shown).

  At the set position (loading state) of the roll paper Pr, the rotational load means 14 (torque limiter) provided at the left end of the roll paper feed unit 10 is passed through a one-way gear 15 as a one-way transmission means. It is comprised so that the drive of the winding motor 11 can be transmitted. The one-way gear 15 is fixed in the forward rotation direction in which the roll paper feeding unit 10 feeds the sheet Pr, and the roll paper feeding unit 10 is configured to freely rotate in the reverse rotation direction in which the sheet Pr is rewound. That is, the roll paper Pr transported by the rotation of the transport motor 42 is in the direction opposite to the transport direction by the rotational load means 14 provided on the shaft portion of the roll paper feed unit 10 by fixing the one-way gear 15 in the forward rotation direction. It is conveyed with force (back tension T) applied. On the other hand, at the time of winding, the one-way gear 15 becomes free so that the driving in the rewinding direction of the winding motor 11 is transmitted. The rotational load means 14 attached to the left shaft of the roll paper feeding unit 10 is configured to be able to rotate with the roll paper feeding unit 10.

  The rotational load means 14 can transmit a rotational force (torque) that is less than or equal to a predetermined value regardless of the direction of rotation. However, when the rotational force that is greater than or equal to a predetermined value is applied, the rotational load means 14 does not transmit the rotation. It functions as follows. That is, it is used to generate a roll brake T (back tension) when the roll paper Pr is sent out and to generate a winding torque when rewinding.

  By applying a constant roll brake T (back tension) between the roll paper Pr and the transport roller 41, the skew of the roll paper Pr can be corrected. Accordingly, it is possible to realize a stable and highly accurate conveyance by removing a shift, a slack, and the like that occur when the user rolls and by applying a certain load to the roll paper Pr.

  A detection gear 17 that transmits the rotation of the roll sheet feeding unit 10 to a rotation detecting unit 60 described later is fixed to the left end of the rotating shaft 16 that rotates with the roll sheet feeding unit 10. The rotation is transmitted to the detection transmission gear 61 of the rotation detecting means 60 by the detection gear 17 that rotates together with the roll sheet feeding unit 10 during conveyance. The detection transmission gear 61 is provided with an encoder film 62 on which a slit for detecting rotation is printed. A sensor unit 63 for detecting and counting the slits is provided on the circumference of the encoder film 62.

  The rotational load means 14 is fixed to the left shaft portion of the roll paper feeding unit 10 by a spring pin (not shown), and projections 18a and 18b are provided on the housing. On the other hand, recesses 20 a and 20 b are provided in the housing of the rotating gear 19 that receives transmission from the winding motor 11 via the one-way gear 15. Since these uneven portions are fitted together, the rotation load means 14, the roll paper Pr, and the rotation gear 19 can be rotated with a rotation force (torque) of a predetermined value or less.

  Next, the image forming unit 30 will be described.

  The image forming unit 30 is provided with a suction platen 33 for guiding and supporting the recording medium in a planar shape while sucking the recording medium, and a carriage 32 that is mounted with the recording head 31 and can reciprocate in the main scanning direction (X direction). ing. In this embodiment, an ink jet recording head 31 is mounted on the carriage 32. By driving the recording head 31 based on the image data in synchronization with the main scanning movement of the carriage 32, ink is ejected from the ejection port (ejection port array) of the recording head toward the recording medium Pr, and the image is recorded. Form. A rail stay 3 is arranged on a main stay 2 arranged in the main scanning direction in the apparatus main body, and a pair of parallel main rail 4 and sub rail 5 are fixed. The carriage 32 is guided and supported through rail bearings 6 and 7 so as to be reciprocally movable along the rails 4 and 5. In this embodiment, the recording apparatus 1 is an ink jet recording apparatus. However, the recording apparatus of the present invention is a recording apparatus that uses other types of recording means such as a laser beam type, a thermal transfer type, a thermal type, and a wire dot type. There may be.

  A suction platen 33 having a plurality of suction holes (not shown) is attached to the upper surface of the lower stay 34 extending in the width direction of the apparatus main body. A suction fan 35 is connected to one end of the lower stay 34 of the sealed cavity structure. By operating the suction fan 35, suction is performed from the suction hole of the suction platen 33 using the lower stay 34 as a suction duct, and the recording sheet Pr is sucked onto the suction platen 33. This prevents paper floating during recording, undulation (cockling) after recording, and the like.

  Next, conveyance correction control of the recording medium conveyance device of the present embodiment will be described.

  FIG. 4 is a schematic diagram illustrating a drive command (speed profile) of a conveyance motor that performs intermittent feeding of the recording medium conveyance device of the present embodiment. In the conveyance correction control of the present embodiment, first, an intermittent feed (one-pass feed) drive command is performed to convey to a carry motor 42 in units of a predetermined length. The drive is transmitted to the transport pulley 46 disposed at the left end of the transport roller 41 via the drive belt 45. The pulse output from the encoder film 47 provided on the transport pulley 46 is counted by the detection sensor 48 and fed back to the transport motor drive command (speed profile) to perform high-precision positioning control.

  The conveyance motor drive command (speed profile) 100 is a so-called trapezoidal drive command for performing acceleration control 101 -constant speed control 102 -deceleration control 103 as shown in FIG. In order to perform high-precision positioning during deceleration, the minute feed control (creep control 104) is performed at a low speed. A speed profile 100 shown in FIG. 4 is an initial target profile 105 as a speed profile before carrying out a conveyance correction described later. In the present embodiment, a conveyance correction amount set in advance by the action state of the force (back tension T) in the direction opposite to the conveyance direction to the recording sheet during conveyance is set to the initial target profile 105 in the creep control 104 area. The conveyance correction is performed by subtracting at.

  The presence or absence of the action of the back tension T is determined by the rotation amount of the roll sheet feeding unit 10, that is, the number of pulses of the rotation detecting means 60 in the acceleration control section and the constant speed control section at the start of conveyance.

  In the present embodiment, as the timing for detecting the back tension T, the control is performed by dividing the acceleration control time into the detection section A and the constant speed control time into the detection sections B, C, and D. When the number of pulses detected in each detection section is equal to or greater than the threshold set for each recording sheet type and each recording mode in each detection section from A to D, it is determined that the roll paper feeding unit 10 has started to rotate due to conveyance. To do. That is, it is determined that the recording sheet has been conveyed in a state where the back tension T is applied from the section where the threshold value is exceeded. On the other hand, when the amount of rotation of the roll paper feeding unit 10 (number of pulses by the rotation detecting means 60) is smaller than the set threshold value, it is determined that the recording sheet has been conveyed in the detection section without the back tension T acting. To do.

  FIG. 5 is a table showing the rotation detection threshold values of the present embodiment. In this embodiment, in addition to setting the threshold value of the rotation speed (number of pulses) for each detection section divided into detection sections A to D, the recording mode is divided into standard, clean, and highest for each detection section. Each threshold is set. That is, in order to reduce the conveyance amount of the recording medium in order to improve the image quality, the distance from the accompanying rotation until the action of the back tension T is reduced. In addition, the threshold value varies depending on the type of roll paper for each knowledge section.

  FIG. 6 is a diagram illustrating a speed profile at the time of conveyance correction of the sheet conveying apparatus of the present embodiment. In this figure, the conveyance correction amount and the speed profile according to the action state of the back tension T in one pass are shown.

  In “State 1”, the rotation amount (number of pulses) of the roll paper feeding unit 10 is smaller than the set threshold shown in FIG. 5 in the detection section A during acceleration control and the detection sections B to D in the constant speed control section. This is a state where (rotation amount <threshold) is detected. That is, it is determined that the sheet is conveyed in a state where the back tension T does not act in most of the one-pass conveyance. This is a state in which the next pass is conveyed in the accompanying state. In this case, the conveyance correction amount is the state 1 correction amount “A”, and the position obtained by subtracting the state 1 correction amount “A” from the initial target profile 105 is the creep target position 110 (speed profile).

  Next, in “state 2” to “state 4”, in the detection section A at the time of acceleration control, the amount of rotation (number of pulses) of the roll sheet feeding unit 10 is detected to be smaller than the set threshold (rotation amount <threshold). State. In addition, the rotation amount (number of pulses) of the roll sheet feeding unit 10 is detected to be equal to or greater than a set threshold value in any one of the detection sections B to D of the constant speed control section. That is, it is determined that the sheet is conveyed in a state where the back tension T is applied from the detected section. This is a state in which the vehicle is rotated in the detection section A during acceleration control, and is conveyed in a state in which it is unwound from the rotation in any of the detection sections B to D. In this case, the conveyance correction amount is changed from the state 2 correction amount “B” to the state 4 correction amount “D” according to the state (detection section) in which the back tension T is detected, and subtracted from the creep control region of the initial target profile 105. To do. In the “state 2”, the speed profile up to the creep position 111 is used. In the “state 3”, the speed profile up to the creep position 112 is set. In “state 4”, the speed profile up to the creep position 113 is used.

  Next, “state 5” is a state in which the rotation amount (number of pulses) of the roll sheet feeding unit 10 is detected to be equal to or greater than a set threshold (rotation amount> = threshold) in the detection section A during acceleration control. That is, it is determined that the sheet is conveyed with the back tension T applied in almost one-pass conveyance. This is a state in which the next pass is transported in the state of being rewound from the accompanying state. In this case, the creep target position is set as the creep position 114. That is, the speed profile is the same as the initial target profile 105 set on the assumption that the back tension T is always applied in the entire detection section.

  FIG. 7 is a table showing the conveyance correction amounts in the present embodiment. Each of the above-described correction amounts (state 1 correction amount “A” to state 4 correction amount “D”) is a conveyance correction amount set in advance according to the roll paper type, the recording mode, and the back tension acting state shown in FIG. One of them is selected.

  FIG. 8 is a block diagram showing a flow of the conveyance correction control in one pass. FIG. 9 is a flowchart showing a procedure for transport correction according to the present embodiment.

  The initial target profile 105 corresponding to the roll paper type, recording mode, and roll paper winding diameter is commanded from the memory 120 to the transport motor 42 via the CPU 121 and the I / F 122, and transport is started (step S1). The rotation amount of the conveyance roller 41 is fed back from the detection sensor 48 of the conveyance encoder, and the rotation is controlled by comparison with the command rotation amount.

  Next, the rotation amount from the sensor unit 63 of the roll encoder unit is sequentially detected in the detection sections A to D during one-pass conveyance (steps S2 to S5), and the conveyance correction amount according to the back tension applied state. Is selected from the memory 120. Then, the conveyance motor 42 is instructed via the CPU 121 and the I / F 122 (steps S7 to S10).

  As described above, by setting the conveyance correction amount within one pass according to the action state of the back tension T during conveyance, highly accurate conveyance can be performed without being affected by the unstable action state of the back tension T. Can do.

(Second Embodiment)
The conveyance correction control according to the first embodiment subtracts the conveyance correction amount from the initial target profile. In this embodiment, the conveyance correction amount is added to the initial target profile.

  FIG. 10 is a diagram illustrating a speed profile at the time of conveyance correction of the sheet conveying apparatus of the present embodiment. A speed profile is set as the initial target profile 140 in consideration of a state in which the back tension T is not applied to the entire area in one pass during conveyance of the recording sheet.

  In “state 1”, the rotation amount (number of pulses) of the roll paper feeding unit 10 is smaller than the set threshold value in the detection section A during acceleration control and the detection sections B to D in the constant speed control section (rotation amount < Threshold) is detected. That is, it is determined that the sheet is conveyed in a state where the back tension T is not effective in most of the one-pass conveyance. In this case, the conveyance correction amount is set to 0, and the speed profile (initial target profile 140) up to the creep position 141 is maintained.

  Next, from “state 2” to “state 4”, in the detection section A during acceleration control, the rotation amount (number of pulses) of the roll sheet feeding unit 10 is detected to be smaller than the set threshold value (rotation amount <threshold value). State. In addition, the rotation amount (number of pulses) of the roll sheet feeding unit 10 is detected to be greater than or equal to a set threshold value in any one of the detection sections B, C, and D of the constant speed control section. That is, it is determined that the sheet is conveyed in a state where the back tension T is applied from the detected section. In this case, the conveyance correction amount is a correction amount (state 2 correction amount “A” to state 4 correction amount “C”) corresponding to the state (detection section) in which the back tension T is detected, and the creep control region of the initial target profile 140. Add to. In the “state 2”, the speed profile up to the creep position 142 is used. In “state 3”, the speed profile up to the creep position 143 is used. In “state 4”, the speed profile up to the creep position 144 is used.

  Next, “state 5” is a state in which the rotation amount (number of pulses) of the roll sheet feeding unit 10 is detected to be equal to or greater than a set threshold (rotation amount> = threshold) in the detection section A during acceleration control. That is, it is determined that the sheet is conveyed with the back tension T applied in almost one-pass conveyance. In this case, the conveyance correction amount is added to the creep control region of the initial target profile 140 as the state 5 correction amount “D”. As these conveyance correction amounts, correction values set in advance according to the type of roll paper, the recording mode, and the roll winding diameter are used.

  As described above, the unstable operation state of the back tension T can be obtained by setting the conveyance correction amount in one pass, that is, in real time according to the operation state of the back tension T at the time of conveyance as in the first embodiment. Highly accurate transfer can be realized without being affected by

(Third embodiment)
In this embodiment, the conveyance correction amount is added to or subtracted from the creep control 153 area according to the applied state of the back tension T, as in the first or second embodiment.

  FIG. 11 is a schematic diagram illustrating a main configuration of the sheet conveying apparatus according to the present embodiment. A roll gear unit 21 that rotates in synchronization with the roll paper is provided at the end of the roll paper feed unit 10 for setting the roll paper. In the configuration of the roll gear unit 21, the winding drive of the winding DC motor 23 is transmitted via the transmission gear 22. The take-up DC motor 23 applies a current that gives a constant addition in the direction opposite to the roll rotation direction during conveyance, and performs a constant addition torque control by feedback-controlling this current. That is, the take-up DC motor 23 adds a back tension T to the conveyed recording sheet. At the time of rewinding, the winding operation can be performed by rotating the winding DC motor 23 in the direction opposite to the conveying direction.

  FIG. 12 is a speed profile at the time of conveyance correction according to the present embodiment. The speed profile of this embodiment is for reducing the conveyance correction amount from the creep control 153 region. The action of the back tension T is determined by detecting the current value, that is, the torque value of the winding DC motor 23. A current corresponding to the set torque is applied to the winding DC motor 23 during conveyance. A change 151 in the applied current that occurs when the current is changed in one pass, that is, when the conveying force is transmitted to the roll sheet feeding unit without looseness of the conveying sheet (the sheet is stretched) is set in advance. It is determined that the back tension T is applied when the amount of change is greater than or equal to the amount of change. The detection section of the back tension T, that is, the detection section of the current change amount to the DC motor 23 is detected in one or a plurality of detection sections as in the first or second embodiment. In FIG. 12, the current change of the DC motor 23, that is, the operating state of the back tension T is detected in the detection section C, the conveyance correction amount corresponding to this operating state is subtracted from the initial speed profile 150, and the creep target position 153 is set. Yes.

  As described above, the back tension T is unstable by setting the transport correction amount in real time in one pass according to the action state of the back tension T during transport as in the first and second embodiments. High-accuracy conveyance can be realized without being affected by the action state.

  In the above-described embodiment, the serial type recording apparatus using the recording head mounted on the carriage has been described as an example. However, the present invention can be similarly applied to a recording apparatus of another recording system, such as a line type recording apparatus that records only by sub-scanning, and may be any apparatus that can obtain the same effect. In the case of using an ink jet recording head, the present invention may be an apparatus using one recording head or an apparatus using a plurality of recording heads using different color inks. Alternatively, an apparatus that uses a plurality of recording heads that use inks of the same color and different densities, or a recording apparatus that combines these may be used.

11 Rewinding motor 14 Rotation load means (torque limiter)
DESCRIPTION OF SYMBOLS 15 One-way gear 16 Rotating shaft 17 Detection gear 19 Rotation gear 21 Roll gear part 22 Transmission gear 23 Winding DC motor 60 Rotation detection means 61 Detection transmission gear 63 Sensor part 70 Rotation detection threshold value 80 Conveyance correction amount 100 Conveyance motor drive command (speed profile) )
Pr Roll recording sheet T Roll brake (back tension)

Claims (5)

Conveying means for conveying the recording medium drawn from the roll paper in units of a predetermined length, rotational load means for acting on the recording medium in a direction opposite to the conveying direction of the recording medium, and acting on the recording medium A recording medium transport apparatus comprising: a determination unit that determines that a force in a direction opposite to the transport direction is not applied;
During the conveyance of the predetermined length of the recording medium, when the force in the direction opposite to the conveyance direction acting on the recording medium is not applied by the determination means, the conveyance of the predetermined length of the recording medium. A recording medium conveying apparatus for correcting an amount.   The determination unit divides the recording medium conveyed during the conveyance of the predetermined length into a plurality of detection sections, and determines that a force in the direction opposite to the conveyance direction acting on the recording medium is not acting. The recording medium conveying apparatus according to claim 1, wherein the recording medium conveying apparatus is a recording medium conveying apparatus.   3. The method according to claim 1, wherein it is determined that a force in the direction opposite to the transport direction acting on the recording medium is not applied using a threshold value set in advance for each detection section. Recording medium transport device.   The recording medium transport apparatus according to claim 1, wherein the correction of the transport amount is set for each of the detection sections.   A recording apparatus comprising the recording medium conveyance device according to claim 1, wherein an image is formed on the recording medium conveyed by the recording medium conveyance device.

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