JP2009226839A - Image recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recording device which is provided with a means for detecting the prediction of the loosening of a recording medium (continuous paper) that is continuously supplied, evacuates a recording head from a recording position to an evacuating position in the case that any loosening is predicted, and prevents the recording head from being damaged by the contact of the recording head with the continuous paper. <P>SOLUTION: A control section 20 monitors the output of a looseness sensor 7 when a carriage 12 is positioned at the evacuation position above at the beginning of recording and when the transporting speed of the continuous paper 6 reaches a recordable speed, and terminates the transporting of the continuous paper 6 to stop the recording process when the loosening of the continuous paper 6 is detected. Also even if the loosening of the continuous paper 6 is not detected at the recordable speed, the control section continues to monitor the output of the looseness sensor 7, evacuates the recording head from the recording position to the evacuation position when the loosening of the continuous paper 6 is detected, and terminates the transportation of the continuous paper 6 to stop the recording process. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image recording apparatus that retracts a recording head from a recording position when slack of continuous paper is detected.

  2. Description of the Related Art Conventionally, as an image recording apparatus, for example, an ink jet printer performs image recording at high speed and high image quality by ejecting ink droplets from a plurality of nozzles of a print head onto a recording medium held and conveyed by a conveying unit.

This ink jet printer is widely used as an office application for recording an image on, for example, a cut sheet-like recording medium (sheet paper).
In recent years, inkjet printers can improve throughput by configuring a line head in which a large number of print heads are arranged in a direction perpendicular to the conveyance direction of the recording medium. It is also used as an industrial application for recording thumbtacks on paper.

  In such an image recording apparatus, in order to obtain high image quality, the interval between the continuous paper and the print head is generally very narrow, for example, 1 mm or less. Even if the print head has a coarse resolution, it has 12 nozzles in 1 mm and has a delicate structure.

  Therefore, for example, in the case of an image recording apparatus using continuous paper, if the continuous paper is loosened and slightly lifted, the paper surface of the loose continuous paper may come into contact with the recording head at the recording unit and the recording head may be damaged. Further, there is a possibility that the nozzles may be damaged even if they are not destroyed, and the original recording characteristics cannot be maintained.

The following proposals have been made for an image recording apparatus that detects such slack in continuous paper and removes the slack.
For example, in Patent Document 1, a photo rotary encoder and a detection lever are provided as slack detection means between the paper feeding position and the printing position, and the paper feed roller is stopped on the downstream side of the recording head based on this detection output. A slack removing roller is driven to remove the slack of the paper. By performing this operation, the sheet and the recording head are prevented from contacting each other.
Japanese Patent Laid-Open No. 06-143717

However, the above Patent Document 1 has the following problems.
In other words, Patent Document 1 employs a configuration in which the slack removal roller disposed downstream is used to remove the slack between the paper feeding position and the slack removal roller. With this configuration, a certain amount of slack is detected after it has occurred, and contact between the recording head and the paper cannot be completely prevented.

  In Patent Document 1, the image recording apparatus is a so-called serial type image recording apparatus in which the recording head reciprocates in the main scanning direction. During recording, the sheet feed roller is stopped once, so that the sheet conveyance is intermittent and the recording head is the sheet. It will be done at a timing not above. That is, the slack removal is performed between so-called lines.

  However, in an image recording apparatus using a line type recording head, since the recording head is generally not operated in the main scanning direction, intermittent sheet conveyance is not performed. For this reason, the slack removal operation cannot be performed between the lines, and the slack removal method as disclosed in Patent Document 1 cannot be used to prevent contact between the recording head and the paper.

  In order to solve the above problems, the present invention detects a slack sign of a continuously supplied recording medium (continuous paper), and when a slack is predicted, the print head is continuously moved from the print position. An object of the present invention is to provide an image recording apparatus that can be retracted vertically above the paper, prevent contact between the recording head and the continuous paper, and prevent damage to the recording head.

  In order to solve the above-described problems, an image recording apparatus of the present invention includes a supply unit that supplies continuous paper, a drum that holds the continuous paper supplied from the supply unit on the outer peripheral surface, and conveys the paper downstream. A recording unit that is arranged to face and records an image on continuous paper, a moving unit that moves the recording unit to record an image on continuous paper, and a retreat position different from the recording position; and a drum Is provided on the downstream side, and has a tension generation unit that generates tension on the continuous paper and a slack detection unit that detects slack of the continuous paper, and when the slack detection unit detects a slack sign of the continuous paper, the moving unit The recording unit is moved to the retracted position by the above.

  According to the present invention, when a slack sign of a continuously supplied recording medium (continuous paper) is detected, and the occurrence of slack is predicted, the print head is retreated from the recording position vertically above the continuous paper, It is possible to provide an image recording apparatus capable of preventing the recording head from contacting the continuous paper and preventing the recording head from being damaged.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram schematically showing a configuration of an image recording apparatus according to the first embodiment. As shown in the figure, the image recording apparatus 1 of this example includes a medium supply system 2, an image recording system 3, and a medium cutting and storing system 4.

  The medium supply system 2 is provided with a continuous paper 6 as a recording medium wound around a supply roller 5 having an encoder (not shown) in the rotating portion, and the continuous paper 6 is continuously supplied to the image recording system 3. . The supply roller 5 is provided with a powder brake (not shown), which functions to give a constant back tension in the direction opposite to the conveying direction of the continuous paper 6. This back tension is controlled to be constant regardless of the winding diameter of the continuous paper 6.

  A slack detection sensor 7 is disposed in the continuous paper conveyance path between the medium supply system 2 and the image recording system 3. The slack detection sensor 7 is, for example, a tension sensor that detects the tension applied to continuous paper.

  The image recording system 3 includes a drum 10 that rotates between two free rollers 8 and 9 on the upstream side and the downstream side in the continuous paper conveyance direction, and conveys the continuous paper 6 by the upper peripheral surface. The drum 10 includes a drive source and an encoder (not shown) on its rotation shaft 11.

  A carriage 12 is disposed above the upper peripheral surface of the drum 10 that conveys the continuous paper 6. Although not particularly illustrated, the carriage 12 is provided with a line type recording head. The carriage 12 is driven up and down as indicated by an arrow a in the figure by a carriage drive unit 13 disposed on the left side thereof, and is configured to be movable between a lower recording position and an upper retracted position.

  A carriage position detection unit 14 is disposed on the right side of the carriage 12. The carriage position detector 14 detects the position of the carriage 12 that moves to the recording position or the retracted position, and positions the carriage 12 at the recording position or the retracted position.

  The carriage drive unit 13 and the carriage position detection unit 14 form a moving unit 19. The carriage 12 positioned at the recording position by the moving unit 19 is transported by the drum 10 and ejects ink droplets from the recording head toward the continuous paper 6 to record a predetermined image.

  An unloading roller pair 15 (15a, 15b) as a tension generating means is disposed further downstream of the downstream free roller 9 described above. An encoder is disposed on the rotation shaft or the rotation side surface of either the roller 15a or 15b of the carry-out roller pair 15.

  An upper roller 15a of the carry-out roller pair 15 is rotationally driven at a constant torque by a tension motor (not shown) and cooperates with the lower roller 15b to send an image from the drum 10 through the free roller 9. The continuous paper 6 is discharged to the medium cutting and storing system 4 while applying tension.

  The medium cutting and storing system 4 includes a cutter 16 and a paper discharge table 17. The image-recorded continuous paper 6 discharged from the image recording system 3 to the medium cutting storage system 4 is cut into a sheet by cutting the front and back of the image recording surface by a cutter 16 and is disposed obliquely below the cutter 16. The paper is discharged onto the paper discharge tray 17 and is sequentially stacked and stored in the paper discharge tray 17.

  FIG. 2 is a block diagram illustrating processing functions of the image recording apparatus 1 having the above configuration. As shown in FIG. 1, the image recording apparatus 1 includes a control unit 20. The control unit 20 includes an image recording control unit 23, a carriage control unit 24, a slack monitoring unit 25, a storage unit 26, and a host device IF (interface) unit 27 connected to the arithmetic processing device 21 via a bus 22. .

  For example, a host device 30 such as a computer is connected to the host device IF unit 27. Connected to the image recording control unit 23 is an image recording unit 32 having a line type recording head shown in FIG. The image recording unit 32 is mounted on the carriage 12.

  The carriage control unit 24 is connected to the carriage drive unit 13 and the carriage position detection unit 14 shown in FIG. The slack sensor 25 shown in FIG. 1 is also connected to the slack monitoring unit 25.

  When image data to be recorded by the image recording apparatus 1 is transmitted from the host apparatus 30 to the image recording apparatus 1 via the host apparatus IF unit 27 together with a recording execution command, first, the image data is stored in a predetermined part of the storage unit 26. Stored in the storage area.

  The arithmetic processing unit 21 is an arithmetic processing unit composed of, for example, a CPU or the like. The arithmetic processing unit 21 analyzes a command transmitted from the host device 30 and confirms that the continuous paper 6 is not slack, and is then temporarily stored in the storage unit 26. The recorded image data is read out, and the image recording images sequentially developed for every several lines in the main scanning direction are transmitted to the image recording control unit 23, and the recording process for the continuous paper 6 is started.

FIG. 3 is a flowchart for explaining a recording process executed while the control unit 20 monitors the looseness of the continuous paper 6.
When the recording process is started, as shown in FIG. 3, it is first determined whether or not the carriage 12 is in the retracted position (step S1). This process is a process of detecting the position of the carriage 12 by the carriage position detection unit 14.

  When the carriage 12 has not reached the retracted position (S1 is No), the carriage control unit 24 drives the carriage driving unit 13 to continue the movement of the carriage 12 toward the retracted position (step S2). The process of S1 is repeated.

  When the carriage position detection unit 14 determines that the carriage 12 has come to the retracted position in the process of step S1 (S1 is Yes), the carriage drive unit 13 stops moving the carriage 12, and FIG. A predetermined tension is applied to the continuous paper by a powder brake (not shown) provided on the supply roller shown and a tension motor of the roller 15a, and the drum 10 is rotated by a drive source (not shown) to start conveying the continuous paper 6. (Step S3).

  Then, the output signal of the encoder of the drum 10 is monitored and it is repeatedly determined whether or not the output signal indicates that the conveyance speed of the continuous paper 6 has reached a recordable speed (step S4, S4). The determination result is No).

  When the conveyance speed of the continuous paper 6 reaches a recordable speed (S4 is Yes), slack detection is started (step S5). This process is a process of determining whether or not the tension detection signal applied to the continuous paper 6 input from the looseness detection sensor 7 to the looseness monitoring unit 25 indicates the looseness of the continuous paper 6.

  Then, when the slack of the continuous paper 6 is not indicated (S6 is No), it is subsequently determined whether or not the carriage 12 is at the retracted position (step S11). Since it has been moved to the retracted position in the process of step S2 (S11 is Yes), the carriage 12 is moved to the recording position (step S12).

  In this processing, the carriage control unit 24 drives the carriage driving unit 13 to move the carriage 12 toward the recording position while monitoring the position of the carriage 12 by the carriage position detection unit 14, and the carriage 12 is moved to the recording position. The carriage position detection unit 14 detects that it has come, stops the carriage 12, and positions the recording head of the image recording unit 32 at the recording position.

  Then, it is determined whether or not the recording head is recording (step S13). Since it is immediately after the recording start process, the recording head is not recording (S13 is No). Under the control, the recording head starts recording on the continuous paper 6 (step S14).

  In this process, the image recording control unit 23 transmits an image recording image to the image recording unit 32 of the carriage 12, and the recording head is applied to the continuous paper 6 conveyed in close contact with the upper peripheral surface of the drum 10 without slack. Thus, the image recording process is executed by controlling to eject ink droplets according to the image recording image.

  Following the above, the control unit 20 determines whether or not the recording is finished (step S15). In this process, all the image data stored in the storage unit 26 is read out and transmitted to the image recording control unit 23, and it is determined whether or not the image recording by the image recording unit 32 is finished. is there.

If the image recording has not been completed yet (No in S15), the process returns to step S6 again, and the processes in steps S6 and S11 to S15 are repeated.
In this repetitive process, the determination in step S11 is No, so the process immediately proceeds from the process in step S11 to the process in step S13. Since the determination in step S13 is Yes, the process immediately proceeds from step S13 to step S15. Transition. That is, only the determination processing in steps S6, S11, S13, and S15 is repeated during recording.

Here, when looseness is detected in the continuous paper 6 in the determination in step S6 (Yes in S6), it is determined whether or not the carriage 12 is in the retracted position (step S7).
Immediately after the recording start process, the carriage 12 has been moved to the retracted position in the process of step S2 (S7 is Yes), so the slack detection process by the slack sensor 7 is terminated (step S9), and the roller 15a of the carry-out roller pair 15 is reached. The tension motor, the drive source (not shown), and the powder brake of the supply roller are stopped, the conveyance of the continuous paper 6 is stopped (step S10), and the process is terminated.

  In addition, when the determination processing of steps S6, S11, S13, and S15 is repeated and the processing of steps S6 and S7 is performed during execution of the recording processing (S7 is No), the carriage 12 is moved to the retracted position. (Step S8), the processing of Steps S9 and S10 is executed.

The process of moving the carriage 12 to the retracted position is the same as the process described in steps S1 and S2.
As described above, in the first embodiment, as a basic form of the present invention, when slack is detected in the continuous paper 6 immediately before the start of the recording process or during the execution of the recording process, the recording head is immediately retracted to the retracted position. Then, the conveyance of the continuous paper 6 is stopped.

As a result, immediately after the slack in the continuous paper 6 is detected, the recording head moves to the continuous paper 6 until the slack is corrected by the maintenance operation and the transport of the continuous paper 6 is restored to the normal transport state without the slack. It is possible to provide an image recording apparatus that can avoid the problem of contact and prevent the recording head from being damaged.
(Second Embodiment)
By the way, in the first embodiment, in order to detect the slack of the continuous paper 6, the slack of the continuous paper 6 is directly detected using the slack sensor 7. In this way, the sign of the slack of the continuous paper 6 is detected, and it is assumed that slack has been detected by using the sign, and the recording head is retracted to the retreat position and the conveyance of the continuous paper 6 is stopped as described above. You may do it. This will be described below as a second embodiment.

  FIG. 4 is a block diagram illustrating processing functions of the image recording apparatus according to the second embodiment. In FIG. 4, the same components or functions as those shown in FIGS. 1 and 2 are given the same reference numerals as those in FIGS.

  As shown in FIG. 4, the block configuration of this example is different from the case of FIG. 2, in place of the output of the slack sensor 7 of FIG. 2, the conveyance information generation unit 33 (encoder of the drum 10), medium rotation detection That is, the outputs of the sensor 34 and the tension generating roller encoder 35 are input to the looseness monitoring unit 25.

  The output of the conveyance information generation unit 33 is the output of the encoder of the drum 10 in FIG. 1, the output of the medium rotation detection sensor 34 is the output of the encoder of the supply roller 5 as the supply unit in FIG. The output of the roller encoder 35 is the output of the encoder of the roller 15a above the carry-out roller pair 15 as the tension generating unit in FIG.

  In this example, the slack monitoring unit 25 shown in FIG. 4 functions as a detection unit that detects the supply linear velocity at which the supply roller 5 indicated by the output of the medium rotation detection sensor 34 (encoder of the supply roller 5) sends out the continuous paper 6. . Here, the supply linear velocity indicated by the output of the medium rotation detection sensor 34 detected by the detection unit is V1.

  Further, the slack monitoring unit 25 also functions as a detection unit that detects the rotational circumferential surface linear velocity (conveyance linear velocity of the continuous paper 6) of the drum 10 indicated by the output of the conveyance information generation unit 33 (encoder of the drum 10). Here, the rotation circumferential surface linear velocity indicated by the output of the conveyance information generation unit 33 detected by the detection unit is V2.

  The slack monitoring unit 25 also functions as a detection unit that detects the conveyance linear velocity at which the continuous paper 6 is conveyed, which is indicated by the output of the tension generation roller encoder 35 (the encoder of the roller 15a above the carry-out roller pair 15). Here, the conveyance linear velocity indicated by the output of the tension generating roller encoder 35 detected by the detection unit is V4.

The reason why the carry-out linear velocity is set to V4 instead of V3 is to make it easier to compare with a third embodiment to be described later.
FIG. 5 is a functional block diagram of the slack monitoring unit 25 described above. As shown in the figure, the slack monitoring unit 25 includes an IF (interface) unit 40, a first comparison unit 41, a second comparison unit 42, a third comparison unit 43, and a determination unit 44 connected to the bus 22. Yes.

  The first comparison unit 41, the second comparison unit 42, and the third comparison unit 43 are each input with the conveyance linear velocity reference value of the continuous paper 6 from the arithmetic processing unit 21 via the IF unit 40, and The first comparison unit 41 receives the encoder output signal of the supply roller 5 from the conveyance information generation unit 33, and the second comparison unit 42 receives the encoder output signal of the drum 10 from the medium rotation detection sensor 34. The comparison unit 43 receives an encoder output signal of the roller 15 a above the carry-out roller pair 15 from the tension generation roller encoder 35.

  The determination unit 44 is configured so that the first comparison unit 41, the second comparison unit 42, or the third comparison unit 43 has a linear velocity indicated by an output signal input from the corresponding encoder corresponding to a conveyance linear velocity input from the IF unit 40. It is determined whether the reference value has been reached (the process of step S4 in the flowchart of FIG. 3), and the determination result is notified to the arithmetic processing unit 21.

  At the same time, the determination unit 44 receives the linear velocities V1, V2, and V4 indicated by the output signals of the encoders from the first comparison unit 41, the second comparison unit 42, and the third comparison unit 43, and compares them. To determine whether the continuous paper 6 is slack.

  The control unit 20 shown in FIG. 4 compares and calculates the linear velocities V1, V2, and V4 described above by the slack monitoring unit 25 shown in FIG. 5 in the slack detection processing of steps S5 and S6 shown in the flowchart of FIG. Based on the result, a sign of the slack of the continuous paper 6 is detected, the appearance of the slack is predicted using the sign, and it is determined that the slack itself has been detected.

  There are three methods for detecting a sign as a basis for the determination of the slack detection, and the slack monitoring unit 25 determines that “supply line speed V1”> “rotating circumferential surface speed V2” or “supply line” When “velocity V1”> “conveyance linear velocity V4” or “rotating circumferential surface linear velocity V2”> “conveyance linear velocity V4”, it is determined that a sign of slack has been detected.

  Also, depending on the diameter of the drum 10, in this example, it is determined that a sign of slack has been detected when the difference in linear velocity in the above comparison calculation is, for example, 1% or more of the velocity reference value. To do. In this case, the reference value of the speed is, for example, 700 mm / second. The diameter of the drum 10 is assumed to be 500 mm, for example.

In this way, in the second embodiment, the slack detection of the continuous paper 6 indicating that it is time to retract the recording head to the retracted position is detected in the upstream, middle, and downstream of the conveyance path of the continuous paper 6. Comparing the transport line speed, the transport line speed on the upstream side is more than a predetermined value over the transport line speed on the downstream side between any two points (1% or more of the transport reference line speed in the example of this embodiment). When it becomes larger, it is determined that a slack (a sign) that has caused the floating of the continuous paper 6 so that the recording head has to be retracted to the retracted position is detected.
(Third embodiment)
FIG. 6 is a diagram schematically showing the configuration of the image recording apparatus according to the third embodiment. The image recording apparatus 45 of this embodiment includes a medium supply system 46, an image recording system 47, a medium cutting system 48, and a discharge system 49.

  First, the medium supply system 46 will be described. In the medium supply system 46, a roll-shaped continuous paper 53 is wound around a rotating shaft 52 provided with a powder brake 51 and is held rotatably. The continuous paper 53 is drawn out from the medium supply system 46 to the image recording system 47 by being pulled out to the image recording system 47 side and supplied.

  The powder brake 51 has a function of applying a constant back tension in the direction opposite to the feeding direction of the continuous paper 53. This back tension is controlled to be constant regardless of the winding diameter of the continuous paper 53.

  A medium rotation detection sensor 54 is disposed in the vicinity of the rotation shaft 52. The medium rotation detection sensor 54 is used for the purpose of detecting the rotation speed of the rotation shaft 52. From the diameter of the roll paper that decreases by the thickness of the continuous paper 53 for each rotation of the rotary shaft 52 and the rotational speed of the rotary shaft 52, the delivery linear speed of the continuous paper 53 delivered from the roll paper is calculated. The calculation result is used to determine whether or not the delivery speed is abnormal.

  Next, the image recording system 47 will be described. First, the image recording system 47 includes a plurality of free rollers 55 (55a, 55b,..., 55h), a first drum 56, a first encoder 57, a second drum 58, a second encoder 59, a drum driving unit 61, A continuous paper 53 transport unit including a tension generation roller 62 having a drive source (not shown) and a tension generation roller encoder 63 is provided.

  Further, the image recording system 47 includes a first carriage 64 corresponding to the first drum 56, a first carriage driving unit 65, a first carriage position detecting unit 66, a second carriage 67 corresponding to the second drum 58, and a second carriage driving. An image recording unit including a unit 68 and a second carriage position detection unit 69 is provided.

  The first carriage driving unit 65 and the first carriage position detecting unit 66 form a first moving unit 28, and the second carriage driving unit 68 and the second carriage position detecting unit 69 form a second moving unit 29. Yes.

  The image recording system 47 carries in the continuous paper 53 sent out from the medium supply system 46 and winds and holds the continuous paper 53 with the first drum 56 so as to be pressed by the two free rollers 55a and 55b. Then, the recording process is performed by transporting directly under the first carriage 64.

  Thereafter, the image recording system 47 winds and holds the continuous paper 53 conveyed while passing through the free rollers 55c and 55d by the second drum 58 so as to be pressed by the two free rollers 55e and 55f. It has a function of transporting it directly below 67 and sending it to the medium cutting system 48 after the recording process.

  Next, the configuration of the first drum 56 will be described. The first drum 56 is an aluminum drum, and the continuous paper 53 can be wound at a wrapping angle of 330 degrees. The first drum 56 corresponds to approximately three A3-size vertical (420 mm) sheets at a wrapping angle of 330 degrees. It is designed in such a circumference.

  The continuous paper 53 is given a vertical drag against the outer peripheral surface of the first drum 56 by the back tension at the beginning of winding and the tension at the end of winding of the first drum 56, and by friction between the first drum 56 and the continuous paper 53. It is held by the first drum 56. The first drum 56 is configured as a driven drum that rotates through the continuous paper 53 by the rotation of the second drum 58.

  The first encoder 57 described above is disposed on the rotation shaft of the first drum 56. The rotation shaft of the first encoder 57 rotates with the rotation of the first drum 56 and outputs a detection pulse corresponding to the rotation position of the first drum 56. This detection pulse is input to a control unit which will be described later, and the pulse information is used by the arithmetic processing unit and the image recording control unit.

In the image recording apparatus 45 of the present embodiment, the first encoder 57 is an encoder that outputs a pulse signal of 18000 pulses per rotation.
The recording resolution in the conveyance direction of the continuous paper 53 is 300 dots / 25.4 cm, and the first encoder 57 is designed to record one line per pulse. As a result, the diameter of the first drum 56 is 25.4 cm ÷ 300 dots × 18000 pulses ÷ circumference π = 485 mm.

After the end of winding of the first drum 56, the continuous paper 53 is conveyed via the free rollers 55c and 55d as described above, and further wound around the second drum 58 and conveyed.
Next, the configuration of the second drum 58 will be described. The second drum 58 has the same configuration as that of the first drum 56, and is configured such that the continuous paper 53 can be wound at a winding angle of 330 degrees.

  The continuous paper 53 is given a vertical drag against the outer peripheral surface of the second drum 58 by the back tension at the start of winding of the second drum 58 and the tension at the end of winding, and is caused by friction between the second drum 58 and the continuous paper 53. It is held by the second drum 58 and conveyed by the driving force of the drum driving unit 61.

  The second drum 58 is configured as a driving drum, and the conveyance speed of the continuous paper 53 is determined by the drum driving unit 61. The conveyance speed command for the drum driving unit 61 is performed by an arithmetic processing unit of a control unit described later.

  In addition, a second encoder 59 having an encoder that outputs a pulse signal of 18000 pulses per rotation is connected to the rotation shaft of the second drum 58 in the same manner as the first drum 56.

  The second encoder 59 outputs a detection pulse corresponding to the rotational position of the second drum 58. This detection pulse is also input to a control unit which will be described later, and the pulse information is used in the arithmetic processing unit and the image recording control unit.

  The tension generating roller 62 is a driving roller that generates a downstream tension of the second drum 58, and the driving torque is controlled so as to be a predetermined tension. This output torque is determined in consideration of the friction coefficient between the continuous paper 53 and the first drum 56 and the second drum 58.

In addition, a tension generation roller encoder 63 is incorporated in the drive source of the tension generation roller 62, and thus the rotational speed of the tension generation roller 62 can be detected.
The continuous paper 53 is delivered from the end of winding of the second drum 58 to the medium cutting system 48 via the tension generating roller 62.

  Here, the medium cutting system 48 will be described. The medium cutting system 48 includes a cutting unit roller 71 and a cutting driving unit 72. The cutting part roller 71 is a spiral cutter having two blades, and has a circumferential length of 420 mm in one circumference of the roller. Since the two blades are arranged at intervals of 210 mm, the continuous paper 53 is cut into a length of 210 mm if the cutting unit roller 71 is driven in synchronization with the conveyance speed of the continuous paper 53.

The image recording apparatus 45 according to the present embodiment uses a continuous paper having a width of 297 mm as the continuous paper 53, and cuts and discharges the paper into an A4 size (297 mm × 210 mm).
The cutting drive unit 72 is a servo motor, and is driven by a pulse train command from a control unit to a servo controller (not shown). Of course, the cutting drive unit 72 is not limited to a servo motor, and may be a stepping motor or the like.

  Next, the discharge system 49 will be described. The discharge system 49 includes discharge tray rollers 73 and 74 and a discharge tray 75. The continuous paper 53 after being cut out vertically from the medium cutting system 48 is changed in the horizontal direction by the paper discharge rollers 73 and 74 and guided to the paper discharge tray 75 without any trouble. The paper discharge rollers 73 and 74 are driving rollers that convey the continuous paper 53 in pairs with free rollers 76 and 77, respectively.

  As described above, in the third embodiment, the medium recording system has only one drum, its encoder, and a carriage corresponding to the drum, compared with the second embodiment. There is no significant change in the transport system and the medium cutting and storing system. The drive motor is disposed only on the second drum, which is the most downstream drum, and the other drums are driven by the friction between the paper and the drum.

  FIG. 7 is a block diagram showing processing functions of the image recording apparatus 45 in the third embodiment. 7, the same functional parts as those in FIG. 4 are given the same reference numerals as those in FIG.

  The control unit 20 shown in FIG. 7 will be described. As shown in FIG. 7, a storage unit 26 in the control unit, an image recording control unit 23, a carriage control unit 24, a slack monitoring unit 25, and a higher-level device IF unit 27 are connected to the arithmetic processing device 21 via a bus 22. The The arithmetic processing device 21 monitors the entire state of the device and gives commands to the respective control units and monitoring units.

  The storage unit 26 stores an operation program of the image recording apparatus 45 and temporarily stores recording data from the host device 30. Further, various adjustment parameters of the image recording apparatus 45 are also stored.

The image recording control unit 23 is connected to a first image recording unit 78 mounted on the first carriage 64 and a second image recording unit 79 mounted on the second carriage 67.
The image recording control unit 23 controls the transmission of the recording image input from the host device 30 and the first encoder 57 to the first image recording unit 78 of the first carriage 64 and the second image recording unit 79 of the second carriage 67. Then, generation control of the image recording timing is performed using the conveyance information input from the second encoder 59.

  The carriage control unit 24 is connected to a first carriage drive unit 65, a first carriage position detection unit 66, a second carriage drive unit 68, and a second carriage position detection unit 69. The carriage control unit 24 performs drive control of the first carriage 64 and the second carriage 67 shown in FIG.

  The arithmetic processing unit 21 instructs the carriage control unit 24 to move the first carriage 64 and the second carriage 67 to the retracted position or the recording position with respect to the first drum 56 and the second drum 58, respectively. Do it.

Further, the slack monitoring unit 25 receives the signals of the first encoder 57, the second encoder 59, the medium rotation detection sensor 54, and the information of the tension generating roller encoder 63.
The slack monitoring unit 25 monitors the conveyance state of the continuous paper 53 using the above information and signals, and notifies the arithmetic processing unit 21 when slack occurs or when slack is predicted. Further, the slack monitoring unit 25 sends the conveyance information obtained from the first encoder 57 and the second encoder 59 to the image recording control unit 23.

  Here, the first and second carriages will be described. The first carriage 64 shown in FIG. 6 includes the first image recording unit 78 shown in FIG. 7, a recording head and a recording head driving unit (not shown). Further, the first carriage 64 is configured to be movable in the vertical direction indicated by the double arrow b in FIG. 6 with respect to the first drum 56 by the first carriage driving unit 65.

  The position of the first carriage 64 is detected by the first carriage position detector 66 and notified to the arithmetic processing unit 21 in FIG. A position where the first carriage 64 is separated from the first drum 56 is referred to as a retracted position, and a position where the first carriage 64 is close to the first drum 56 is referred to as a recording position.

  In the image recording apparatus 45 of the present embodiment, the separation distance between the recording heads mounted on the first drum 56 and the first carriage 64 is 100 mm at the retracted position and 1 mm at the recording position.

  Similarly to the first carriage 64, the second carriage 67 also includes a second image recording unit 79, a recording head and a recording head driving unit (not shown). The second carriage 67 is configured to be movable in the vertical direction indicated by the double-directional arrow c in FIG. 6 with respect to the second drum 58 by the second carriage driving unit 68.

  The position of the second carriage 67 is detected by the second carriage position detector 69 and notified to the arithmetic processing unit 3 in FIG. A position where the second carriage 67 is separated from the second drum 58 is referred to as a retracted position, and a position where the second carriage 67 is close to the second drum 58 is referred to as a recording position.

  In the image recording apparatus 45 of the present embodiment, the separation distance between the recording heads mounted on the second drum 58 and the second carriage 67 is 100 mm at the retracted position and 1 mm at the recording position.

  FIG. 8 is a functional block diagram of the slack monitoring unit 25 in the control unit 20 of this example. As shown in the figure, in this example, the sag monitoring unit 25 includes a comparison unit connected between the IF unit 40 and the determination unit 44, the first comparison unit 41, the second comparison unit 42, and Compared to the case of the third comparison unit 43, the fourth comparison unit 80 is increased by one.

  However, in this example, it is the second comparison unit 42 that is actually added, and the third comparison unit 43 and the fourth comparison unit 80 are the second comparison unit 42 and the third comparison unit in the case of FIG. 43.

  Also in this example, the first comparison unit 41, the second comparison unit 42, the third comparison unit 43, and the fourth comparison unit 80 convey the continuous paper 53 from the arithmetic processing unit 21 via the IF unit 40, respectively. A linear velocity reference value is input.

  At the same time, an encoder output signal is input from the first encoder 57 to the first comparator 41, an encoder output signal is input from the second encoder 59 to the second comparator 42, and the third comparator 43 receives the encoder output signal. A rotation speed detection signal is input from the medium rotation detection sensor 54, and an encoder output signal is input to the fourth comparison unit 80 from the tension generation roller encoder 63.

  In this example, the slack monitoring unit 25 shown in FIG. 8 functions as a detection unit that detects the supply linear velocity at which the rotation shaft 52 indicated by the output of the medium rotation detection sensor 54 feeds the continuous paper 6, and detects the detected medium rotation. The supply linear velocity indicated by the output of the sensor 54 is V1.

  Further, the slack monitoring unit 25 functions as a detection unit that detects the rotational peripheral surface linear velocity (conveyance linear velocity of the continuous paper 6) of the first drum 56 indicated by the output pulse of the first encoder 57. Rotational surface linear velocity indicated by the output of the first encoder 57 is V2.

  Further, the slack monitoring unit 25 functions as a detection unit that detects the rotational circumferential surface linear velocity (conveying linear velocity of the continuous paper 6) of the second drum 58 indicated by the output pulse of the second encoder 59. 2 Rotational surface linear velocity indicated by the output of the encoder 59 is V3.

  The slack monitoring unit 25 also functions as a detection unit that detects the conveyance linear velocity of the continuous paper 6 carried out by the tension generation roller 62 indicated by the output of the tension generation roller encoder 63. The conveyance linear velocity indicated by the output is V4.

  The determination unit 44 inputs, from the IF unit 40, the linear velocity indicated by the signal input from the corresponding detection unit to the first comparison unit 41, the second comparison unit 42, the third comparison unit 43, or the fourth comparison unit 80. It is determined whether or not the reference value of the conveyance linear velocity to be reached is reached (the process of step S4 in the flowchart of FIG. 3), and the determination result is notified to the arithmetic processing unit 21.

  At the same time, the determination unit 44 includes linear velocities V1, V2, V3 indicated by output signals of the detection units from the first comparison unit 41, the second comparison unit 42, the third comparison unit 43, and the fourth comparison unit 80. And V4 are received and compared to determine whether the continuous paper 6 is slack.

  The control unit 20 shown in FIG. 7 compares and calculates the linear velocities V1, V2, V3, and V4 described above by the slack monitoring unit 25 shown in FIG. 8 in the slack detection processing in steps S5 and S6 shown in the flowchart of FIG. Based on the result, a sign of slack in the continuous paper 6 is detected, and the appearance of slack is predicted (predicted) based on the sign, and it is determined that the slack itself has been detected.

  There are six predictive detection methods that are the basis for this slack detection determination. That is, the sag monitoring unit 25 as a sag detection unit is a sign of sag when V1> V2, or V1> V3, or V1> V4, or V2> V3, or V2> V4, or V3> V4, respectively. Is determined to have been detected.

  Based on this determination, when slack is detected in the processing shown in the flowchart of FIG. 3, the carriage is controlled to retract to the retracted position. In the case of this example, in steps S2 and S8 in the flowchart of FIG. 3, the carriage is always moved to the retracted position in parallel with respect to the first and second carriages 64 and 67.

  Accordingly, the recording heads mounted on the first and second carriages 64 and 67 are 1 mm with respect to the first drum 56 and the second drum 58, that is, with respect to the continuous paper 6 conveyed by these drums. The recording position is moved from the recording position to the retracted position of 100 mm to a position where the separation distance is increased, and the breakage of the recording head caused by the floating of the continuous paper 6 is prevented.

  In the third embodiment, the example in which two drums are used as the medium carrier has been shown. However, the configuration of the line head is simplified, and four colors or six colors including light cyan and light magenta are provided for each color. Even when a total of six recording units are composed of six line heads and six drums, the recording head is retracted to the retracted position by detecting a sign of slack in the continuous paper by the above-described method, and continuously. It is possible to prevent the recording head from being damaged due to the contact between the paper and the recording head.

  This will be briefly described. When two or more drums (six in this example) are provided as described above, the most downstream drum (sixth drum in this example) is a driving drum, and the other drums are driven drums. Each unit of the continuous paper conveyance system is provided with a detection unit that can detect the medium conveyance linear velocity by the rotation detection sensor and the encoder described above.

  The medium rotation detection sensor of the medium supply system is used as the first detection unit, and the supply linear velocity of the medium supply system indicated by the detection result is V1. The plurality of encoders that respectively detect the rotational peripheral linear velocities of the plurality of drums are set as a plurality of detection units, and the conveyance linear velocity indicated by the information of the detection units is set to V2 (i) (i = 1, 2, 3, ..., n) (n = 6 in this example).

The tension generating roller encoder of the tension generating roller unit of the medium discharging unit is set as the third detecting unit, and the discharge linear velocity of the medium discharging unit indicated by the detection result is set to V4.
The looseness monitoring unit includes a detection unit on the upstream side of the two detection units adjacent to each other along the conveyance direction of the continuous paper among the first detection unit, the plurality of detection units, and the third detection unit. The detection result of the side detector is “V1> V2 (1)” or “V2 (i)> V2 (i + 1)” or “V2 (n)> V4” (in this example, “V2 (6)> V4”). ), It is determined that a sign of continuous paper slack has been detected.

  As described above, in an image recording apparatus having a recording medium conveyance system in which continuous paper is conveyed by a plurality of drums, adjacent in the conveyance direction among a plurality of detection units that detect a recording medium conveyance linear velocity of the recording medium conveyance system. By knowing the detection results of the upstream detection unit and the downstream detection of the two detection units provided, it is possible to predict the slack of the continuous paper and prevent the recording head from being damaged.

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not change the summary.

It is a figure which shows typically the structure of the image recording device in 1st Embodiment. It is a block diagram which shows the processing function of the image recording device in 1st Embodiment. 6 is a flowchart illustrating a recording process that is executed while monitoring looseness of continuous paper by the control unit of the image recording apparatus according to the first embodiment. It is a block diagram which shows the processing function of the image recording device in 2nd Embodiment. It is a block diagram which shows the processing function of the slack monitoring part of the control part in the image recording device of 2nd Embodiment. It is a figure which shows typically the structure of the image recording device in 3rd Embodiment. It is a block diagram which shows the processing function of the image recording device in 3rd Embodiment. It is a block diagram which shows the processing function of the slack monitoring part of the control part in the image recording device of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image recording device 2 Medium supply system 3 Image recording system 4 Medium cutting | disconnection storage system 5 Supply roller 6 Continuous paper 7 Slack detection sensor 8, 9 Free roller 10 Drum 11 Rotating shaft 12 Carriage 13 Carriage drive part 14 Carriage position detection part 15 ( 15a, 15b) Unloading roller pair 16 Cutter 17 Discharge stand 18 Tension generating unit 19 Moving unit 20 Control unit 21 Arithmetic processing device 22 Bus 23 Image recording control unit 24 Carriage control unit 25 Sag monitoring unit 26 Storage unit 27 Host device IF ( Interface) unit 28 First moving unit 29 Second moving unit 30 Host device 32 Image recording unit 33 Conveyance information generating unit (encoder)
34 Medium rotation detection sensor 35 Tension generating roller encoder 40 IF (interface) unit 41 First comparison unit 42 Second comparison unit 43 Third comparison unit 44 Determination unit 45 Image recording device 46 Medium supply system 47 Image recording system 48 Medium cutting system 49 Discharge system 50 Speed detection unit 51 Powder brake 52 Rotating shaft 53 Continuous paper 54 Medium rotation detection sensor 55 (55a, 55b,..., 55h) Free roller 56 First drum 57 First conveyance information generation unit (encoder)
58 2nd drum 59 2nd conveyance information generation part (encoder)
61 Drum Drive Unit 62 Tension Generation Roller 63 Tension Generation Roller Encoder 64 First Carriage 65 First Carriage Drive Unit 66 First Carriage Position Detection Unit 67 Second Carriage 68 Second Carriage Drive Unit 69 Second Carriage Position Detection Unit 71 Cutting Unit Roller 72 Cutting drive unit 73, 74 Paper discharge roller 75 Paper discharge plate 76, 77 Free roller 78 First image recording unit 79 Second image recording unit 80 Fourth comparison unit

Claims (8)

A supply unit for supplying continuous paper;
A drum that holds the continuous paper supplied from the supply unit on an outer peripheral surface and conveys the continuous paper downstream;
A recording unit arranged to face the drum and record an image on the continuous paper;
A moving unit that moves the recording unit to a recording position for performing image recording on the continuous paper and a retreat position different from the recording position;
A tension generator provided downstream of the drum and generating tension on the continuous paper;
A slack detecting unit for detecting slack of the continuous paper;
Have
An image recording apparatus, wherein when the slack detecting unit detects a sign of slack in the continuous paper, the moving unit moves the recording unit to the retracted position.   The image recording apparatus according to claim 1, wherein the slack detection unit is a tension sensor that is provided between the supply unit and the recording unit and detects a tension applied to the continuous paper. The slack detection unit is
A detection unit that detects at least the supply linear velocity V1 of the continuous paper supplied from the supply unit; and a detection unit that detects the rotational circumferential linear velocity V2 of the drum,
When the detection results by the two detection units indicate that “V1> V2”, it is determined that the sign of looseness of the continuous paper has been detected.
The image recording apparatus according to claim 1. The slack detection unit is
A detection unit that detects at least the supply linear velocity V1 of the continuous paper supplied from the supply unit; and a detection unit that detects the conveyance linear velocity V4 of the continuous paper in the tension generation unit;
When the detection results by the two detection units indicate that “V1> V4”, it is determined that a sag sign of the continuous paper has been detected;
The image recording apparatus according to claim 1. The slack detection unit is
A detection unit that detects at least the rotational circumferential linear velocity V2 of the drum; and a detection unit that detects a conveyance linear velocity V4 of the continuous paper in the tension generation unit,
When the detection results by the two detection units indicate that “V2> V4”, it is determined that a sag sign of the continuous paper has been detected;
The image recording apparatus according to claim 1. Two drums are provided, a downstream drum is a driving drum, an upstream drum is a driven drum, a detection unit that detects a rotational peripheral surface linear velocity V2 of the driven drum, and a rotational peripheral surface of the driving drum A detection unit for detecting the linear velocity V3,
In the looseness detection unit, the detection result by each of the detection units is “V1> V2”, “V1> V3”, “V1> V4”, “V2> V3”, “V2> V4”, or “V3> V4”. It is determined that a sign of looseness of the continuous paper has been detected when indicating that there is
The image recording apparatus according to claim 1.   The image recording apparatus according to claim 1, wherein the moving unit is in the retracted position when the drum is accelerating or decelerating.   Each said detection part is equipped with an encoder in a rotation part, respectively, Each said linear velocity is calculated from the output pulse signal of each said encoder, The one of Claim 3 thru | or 6 characterized by the above-mentioned. Image recording device.