JP2012246109A - Conveyance device, printing device, and conveyance method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conveyance device that transfers a sheet by two pairs of rollers to a position for treating the same, and can eliminate the action of back tension on a downstream roller without making the device larger.SOLUTION: In the conveyance device that includes: an upstream roller delivering a sheet-like medium to be treated to a conveyance path; a downstream roller for supplying the delivered medium to a position for treating the same; and a control part controlling the drive of the upstream roller and downstream roller to cause the same to convey the medium to be treated at a constant speed, the control part determines the timing of starting the upstream roller and downstream roller upon starting their conveyance operation, based on the information relating to their behavior shown until the speed of conveying a sheet reaches the constant speed in the previous conveyance operation of the upstream roller and downstream roller.

Description

  The present invention relates to an apparatus that conveys a sheet-like object to a processing position with two sets of rollers, and more particularly to an apparatus that can eliminate the action of back tension on a downstream roller without increasing the scale of the apparatus. .

  Conventionally, since an apparatus such as a printer performs processing on a sheet-like medium such as paper, an apparatus for conveying the sheet-like object is required. As such a conveyance device, a commonly used one is, for example, an upstream roller that supplies a medium to a conveyance path from a portion that stores a sheet-like medium, and printing that supplies the supplied medium along the conveyance path. And a downstream roller that conveys the processing to a position where the processing is performed.

  In such a transport apparatus, it is required to accurately control the supply speed of the medium from the downstream roller in order to execute processing such as printing on the transported medium with high quality with high accuracy. However, if there is a back tension pulled from the upstream side in the downstream roller, there is a problem that it is difficult to control.

  Therefore, as a technique for overcoming this problem, a proposal as in Patent Document 1 below has been conventionally made. This document shows that the drive timing of the upstream roller is advanced and the amount of conveyance is increased.

JP 2008-56367 A

  However, in the method described in Patent Document 1, the driving timing that is advanced and the method of increasing the conveyance amount are fixedly determined regardless of the situation, so that appropriate control is always performed according to the changing conveyance state. There are issues in terms. For example, the force applied to each roller and the transport force vary depending on the wear status of each roller and the storage status of the media (or roll diameter if the media is roll paper). The medium may become loose between the side roller and the downstream roller, or on the contrary, the medium may become too slack and rub against a member in the transport path, and back tension occurs on the downstream roller. There is a fear. Further, there is a problem that the apparatus scale must be increased in order to keep a large amount of slack so that the slack does not disappear and to prevent the slack from coming into contact with members in the transport path.

  Accordingly, an object of the present invention is an apparatus that conveys a sheet-like material to a processing position with two sets of rollers, which can eliminate the action of back tension on a downstream roller without increasing the scale of the apparatus. Is to provide a device, etc.

  In order to achieve the above object, one aspect of the present invention includes an upstream roller that feeds a sheet-like processed medium to a conveyance path, a downstream roller that supplies the fed medium to a processing position, and And a controller that controls the driving of the upstream roller and the downstream roller to convey the medium to be processed at a constant speed, wherein the control unit includes the upstream roller and the The start timing of the upstream roller and the downstream roller at the start of the transport operation is determined based on information indicating the behavior of the downstream roller up to the constant speed.

  Furthermore, in the above-described invention, a preferable aspect thereof is characterized in that the start timing is determined so as to delay the start timing of the downstream roller with respect to the upstream roller.

  Furthermore, in the above-described invention, one aspect thereof is that the information indicating the behavior until reaching the constant speed is the time from the start of the upstream roller and the downstream roller to the constant speed. It is characterized by.

  Furthermore, in the above invention, another aspect is that the information indicating the behavior up to the constant speed is obtained by starting the upstream roller and the downstream roller, and starting the upstream roller at a constant speed. The amount of the medium to be processed is conveyed by each of the upstream roller and the downstream roller before the time required to reach has reached.

  Furthermore, in the above-described invention, a preferred aspect is characterized in that information indicating a behavior up to the constant speed and information indicating a relationship between the activation timings are stored in advance for each type of the medium to be processed.

  Furthermore, in the above-described invention, a preferable aspect thereof is characterized in that the medium to be processed is supplied to the upstream roller from a state where the medium to be processed is held in a roll shape.

  In order to achieve the above object, another aspect of the present invention is to provide a printing apparatus that includes the transport device described above and that performs printing on the target medium at the processing position.

  In order to achieve the above object, still another aspect of the present invention provides an upstream roller that feeds a sheet-like processed medium to a conveyance path, a downstream roller that supplies the fed medium to a processing position, A control unit that controls driving of the upstream roller and the downstream roller to transport the medium to be processed at a constant speed, wherein the control unit includes the upstream unit during the previous transport operation. The start timing of the upstream roller and the downstream roller at the start of the transport operation is determined based on information indicating behavior of the side roller and the downstream roller up to the constant speed.

  Further objects and features of the present invention will become apparent from the embodiments of the invention described below.

It is a schematic block diagram concerning the example of an embodiment of a printing device provided with a conveyance device to which the present invention is applied. FIG. 6 is a diagram illustrating an example of behavior of a paper feed roller 29 and a transport roller 30 at the start of a transport operation. 6 is a flowchart illustrating an example of a process executed by a conveyance control unit 22; It is a figure for demonstrating wait time (DELTA) T. It is the figure which showed an example of Duty value of motors 27A and 27B with time.

  Embodiments of the present invention will be described below with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention. In the drawings, the same or similar elements are denoted by the same reference numerals or reference symbols.

  FIG. 1 is a schematic configuration diagram according to an embodiment of a printing apparatus including a transport device to which the present invention is applied. The printer 2 shown in FIG. 1 is a printing apparatus according to the present embodiment, and the printing apparatus prints a sheet 26 of a printing medium with a feed roller 29 (upstream roller) and a conveyance roller 30 (downstream roller). The paper is transported to a position and printing processing is performed. In each transport operation, the drive start timing of both rollers is determined based on the behavior at the start of the drive of both rollers in the previous transport operation, and the paper between the two rollers The 26 slacks are always kept constant.

  As shown in FIG. 1, the printer 2 is a device that executes a printing process in response to an instruction from a host device 1 such as a computer. Here, as an example, the printer 2 uses a roll paper 25 as a paper 26. 26 is a printing apparatus that continuously performs printing while transporting 26.

  In FIG. 1, the schematic configuration of the printer 2 is schematically illustrated. However, the printer 2 includes a printing system that controls printing contents and executes a printing process on the paper 26 and a transport system that transports the paper 26.

  The printing system is provided with a printing control unit 21, which receives a printing instruction from the host device 1, issues a printing command to the head unit 23 in accordance with the instruction, and conveys the conveyance control unit 22. The paper 26 is requested to be conveyed. The head unit 23 executes a printing process on the paper 26 that moves between the head unit 23 and the platen 24 at a predetermined speed in accordance with the print command.

  In the transport system, as shown in FIG. 1, the paper 26 held as the roll paper 25 in the print medium storage location is transported to the head unit 23 along the transport path 33, and then, via the paper discharge roller 32. Then, a transport operation for discharging from the printer 2 is executed.

  For paper conveyance to the head unit 23, a paper feed roller 29 (upstream roller) and a conveyance roller 30 (downstream roller) driven by corresponding motors (27A and 27B) are provided. On both the rollers, driven rollers (28A and 28B) are disposed in a state where pressure is applied to the side of the paper 26, with the paper 26 facing each other.

  The paper feed roller 29 has a function of supplying the paper 26 held as the roll paper 25 to the transport path 33, rotates by the torque of the motor 27A transmitted through the speed reducer, and presses the paper 26 together with the driven roller 28A. The paper 26 is moved by the friction force between the two.

  The transport roller 30 has a function of transporting the paper 26 supplied by the paper feed roller 29 to the printing position, that is, to the position of the head unit 23, and is rotated by the torque of the motor 27B transmitted through the speed reducer. The paper 26 is moved by the friction force between the paper 26 pressed together with the driven roller 28B.

  The paper feed roller 29 and the transport roller 30 are provided with encoders 31A and 31B, respectively, and the rotational speeds of both rollers detected by them are notified to the transport control unit 22.

  The conveyance control unit 22 illustrated in FIG. 1 is a part that controls the conveyance system, and controls the conveyance operation of the paper 26 based on an instruction from the print control unit 21. In particular, the drive and stop of the paper feed roller 29 and the transport roller 30 are controlled so that the paper 26 is favorably transported to the printing position. The drive / stop control of the paper feed roller 29 and the transport roller 30 has a feature of the printer 2, and the specific contents thereof will be described later.

  Although not shown, the transport control unit 22 is configured by a CPU, a ROM, a RAM, an NVRAM (nonvolatile memory), and the like, and the processing executed by the transport control unit 22 is mainly a program stored in the ROM. It is executed by the CPU operating according to the above.

  Each data necessary for the processing is temporarily stored in the RAM, and each drive data during the transport operation necessary for driving / stopping control of the paper feed roller 29 and the transport roller 30 and a wait time ΔT described later are here. Is remembered. Each stored drive data includes the drive start time, the transport speed, and the corresponding duty value of the motor 27 (here, the amount of current supplied to the motor 27) of the paper feed roller 29 and the transport roller 30.

  The NVRAM stores in advance relation information for determining the wait time ΔT. The relevant information will be described later.

  In addition, the said conveyance system containing the paper feed roller 29, the conveyance roller 30, and the conveyance control part 22 corresponds to the conveyance apparatus of this invention.

  The printer 2 having the above-described configuration is characterized by the conveyance control of the paper 26, and the specific contents thereof will be described below.

  As described above, since the printer 2 executes the printing process on the paper 26 that is conveyed at a predetermined (constant) speed, the conveyance control unit 22 starts the paper feeding roller 29 when the printing process is started. And it controls so that the conveyance speed of the conveyance roller 30 becomes quick to the said predetermined speed, the conveyance speed is maintained until a printing process is complete | finished, and both rollers are stopped when a printing process is complete | finished. The transport operation and the transport process are repeatedly executed every time the print process is executed.

  Further, when the paper 26 is set for the first time, the transport control unit 22 can perform a certain slack (for example, a slack as shown in FIG. 1) on the paper 26 between the paper feed roller 29 and the transport roller 30. Both rollers are controlled to convey the paper 26 to a predetermined position. As described above, this is to prevent back tension from acting on the transport roller 30, so that the paper 26 can always be supplied from the transport roller 30 to the printing position at a constant speed. Become.

  Further, since the paper feed roller 29 receives a force for pulling out the paper 26 from the roll paper 25 positioned on the upstream side as a back tension, the back tension of the paper feeding roller 29 is usually larger than that of the transport roller 30 during the transport of the paper 26. Will receive.

  Accordingly, at the start of each of the transport operations, the paper feed roller 29 tends to take more time to reach the predetermined speed. FIG. 2 is a diagram illustrating an example of the behavior of the paper feed roller 29 and the transport roller 30 at the start of the transport operation. In the figure, the horizontal axis represents the elapsed time (T) from the start of driving, and the vertical axis represents the conveyance speed (V) of each roller. A curve A in the graph shows the behavior of the paper feed roller 29, and a curve B shows the behavior of the transport roller 30.

  As described above, since a larger back tension acts on the paper feed roller 29 compared to the transport roller 30, as shown in FIG. 2, the rise of the transport speed until the target predetermined speed is reached, as shown in FIG. (Curve A) becomes gentler. Therefore, there is a difference in the amount of paper transported by both rollers until the both rollers reach the predetermined speed. In the example illustrated in FIG. 2, a conveyance amount difference (ΔL) corresponding to the area formed between the curve B and the curve A is generated.

  Therefore, if both rollers are activated simultaneously at the start of the above-mentioned transport operation, the transport roller 30 transports more by the transport amount difference (ΔL) until both rollers reach a predetermined speed and are controlled with the same transport amount. become. This is to reduce the slack of the paper 26 described above, and there is a possibility that the slack may be eliminated depending on the difference in the transport amount.

  Therefore, the transport control unit 22 of the printer 2 performs control so that the slack generated in the initial state can be kept substantially constant during each transport operation. The specific control contents will be described below.

  FIG. 3 is a flowchart illustrating a procedure of processing executed by the transport control unit 22. Hereinafter, the control content of the above-described transport operation will be described with reference to FIG. This control is based on the idea that the difference in the conveyance amount at the start of driving described above is eliminated by delaying the activation timing of the conveyance roller 30, and the activation timing is determined at that time, such as the remaining amount of the roll paper 25. This is to be determined on the basis of drive data at the time of the previous transport operation, which well represents the apparatus status of the above. Further, as the drive data, the rising time difference between the paper feed roller 29 and the transport roller 30 (the time difference until the predetermined speed is reached), the transport amount difference until the paper feed roller 29 and the transport roller 30 rise up, and the predetermined data A method using each of the duty value differences of the motors 27 of the paper feeding roller 29 and the conveying roller 30 after reaching the speed can be executed.

  In each transport operation, first, when the transport control unit 22 receives a paper transport start instruction from the print control unit 21 (step S1), the transport control unit 22 acquires the value of the wait time ΔT held in the RAM (step S2). ). The wait time ΔT is a waiting time for delaying the start timing of the transport roller 30 described above, and is information that is determined after the end of each transport operation and retained for the next transport operation. A specific determination method will be described later. Note that in the case of the first transport operation after the printer 2 is activated, a predetermined default value held in the NVRAM is acquired. Further, the value of the wait time ΔT determined during each transport operation may be stored in the NVRAM and obtained from there.

  Further, after the above instruction, the transport control unit 22 starts driving the paper feed roller 29 (step S3). That is, the motor 27A is activated, and then the control is continued so that the conveyance speed of the paper feed roller 29 becomes the target predetermined speed. The conveyance control unit 22 performs drive control of the paper feed roller 29 and the conveyance roller 30 by PID control based on the detection results of the encoders 31A and 31B.

  Next, after the driving of the paper feed roller 29 is started, the transport control unit 22 waits for the acquired wait time ΔT to elapse (step S4), and starts driving of the transport roller 30 (step S5). That is, the motor 27B is activated, and then the control is continued so that the transport speed of the transport roller 30 becomes the target predetermined speed.

  Thereafter, when the paper feed roller 29 and the transport roller 30 reach the predetermined speed, the constant speed drive control is continued for both rollers (step S6).

  Thereafter, when a conveyance stop instruction is received from the print control unit 21 (step S7), the conveyance control unit 22 performs control to stop driving of the paper feed roller 29 and the conveyance roller 30 (step S8). In this control, each roller may be simply controlled so as to make the speed zero, but preferably, the rollers are stopped so that the transport amount of both rollers in the current transport operation is the same. Execute. Thereby, the slack of the paper 26 between the paper feed roller 29 and the transport roller 30 at the start of the transport operation is held.

  In this way, when both rollers are stopped and the current transport operation is completed, the transport control unit 22 determines the weight in the next transport operation from the driving status of the paper feed roller 29 and the transport roller 30 in the current transport operation. Time ΔT is determined and stored in the RAM (step S9).

  The wait time ΔT is for overcoming the difference in transport amount due to the difference in behavior of the paper feed roller 29 and the transport roller 30 at the start of driving. Therefore, the wait time ΔT is determined from the behavior at the start of driving of both rollers. Can take a way to determine. Specifically, as described above, as one method, it is obtained from the rise time difference between the paper feed roller 29 and the transport roller 30.

  FIG. 4 is a diagram for explaining the wait time ΔT. FIG. 4A shows the change in speed over time when the paper feed roller 29 and the transport roller 30 start to drive at the same time as in the graph shown in FIG. It corresponds to ΔT1. That is, the difference in required time from the start of driving of each roller until the target predetermined speed is reached.

  FIG. 4B shows changes in transport speed over time of the paper feed roller 29 and the transport roller 30 when the control in the printer 2 described with reference to FIG. 3 is executed. As described above, the driving start of the transport roller 30 indicated by the curve B is delayed by the wait time ΔT from the driving start of the paper feed roller 29 indicated by the curve A. As a result, by the time when both of the two rollers reach the target predetermined speed (T3 in the figure), the amounts conveyed by both rollers are substantially the same (the areas of ΔL1 and ΔL2 in the figure are substantially the same). ), The slackness of the paper 26 is kept substantially constant during the transport operation.

  Since it can be said that the rise time difference ΔT1 and the wait time ΔT are substantially proportional to each other, a proportional coefficient k1 of ΔT = k1 × ΔT1 is determined in advance by experiment, and the information is stored in the NVRAM as the relation information described above. Keep it. Therefore, in this method, for the paper feed roller 29 and the transport roller 30, the time from the start of driving to the arrival of the predetermined speed is obtained, and in the example shown in FIG. 4B, TA and TB are obtained, ΔT1 is calculated from the difference, and the wait time ΔT is determined from the relationship ΔT = k1 × ΔT1 using the proportionality coefficient k1 which is the relationship information.

  Each drive data stored in the RAM described above is used to determine the wait time ΔT, but these data are appropriately acquired and stored by the transport control unit 22. Further, the transport speed of the paper feed roller 29 and the transport roller 30 and the corresponding duty value of the motor 27 (here, the amount of current supplied to the motor 27) are stored at predetermined time intervals.

  The second method is a method of determining from the conveyance amount difference ΔL until the paper feed roller 29 and the conveyance roller 30 rise. Also in this case, since it can be said that the conveyance amount difference ΔL and the wait time ΔT have a substantially proportional relationship, a proportional coefficient k2 of ΔT = k2 × ΔL is determined in advance by experiment, and the information is related to the relationship described above. Information is stored in NVRAM as information. Therefore, in this method, the paper feed roller 29 and the transport roller 30 are each in the time from the start of driving until the predetermined speed is reached after the start of driving the paper feed roller 29 (TA shown in FIG. 4B). 26 is obtained, ΔL is calculated from the difference between them, and the wait time ΔT is determined from the relationship of ΔT = k2 × ΔL using the proportionality coefficient k2 which is the relationship information.

  In the example shown in FIG. 4B, the conveyance amount during acceleration of the paper feed roller 29 is the conveyance amount from time T1 to T3, and the conveyance amount during acceleration of the conveyance roller 30 is from T2 to T4. ΔL is calculated from the difference between these carry amounts.

  Next, the third method will be described. In this method, the difference in behavior between the paper feed roller 29 and the transport roller 30 at the start of driving is measured by the duty value difference ΔD between the motors 27 of the paper feed roller 29 and the transport roller 30 after reaching the predetermined speed. To do. That is, the wait time ΔT is determined from the duty value difference ΔD.

  FIG. 5 is a diagram showing an example of the duty values of the motors 27A and 27B over time. The duty value indicates the amount of current supplied to each motor 27 as a relative value, and the larger this value, the greater the force to be applied to the roller.

  In FIG. 5, the duty values of the motors 27A (curve A) and 27B (curve B) from the start of driving of the paper feed roller 29 and the transport roller 30 are shown. Usually, since a large force is required at the time of startup, the Duty value has a mountain shape as shown in FIG. 5 and becomes a substantially constant Duty value after reaching the target speed.

  For two rollers to be controlled to the same target speed, a larger duty value means that the driving load is larger, that is, the back tension acting on the paper feeding roller 29 is larger. Show. Therefore, it is possible to measure the above-described rise delay at the start of driving based on the duty value difference. Therefore, in this method, the wait time ΔT is determined from the duty value difference. Further, the duty value difference to be used is not stable because the duty value fluctuates greatly in the control at the start of driving. The duty value difference ΔD in the band) is used.

  Also in this case, it can be said that the duty value difference ΔD and the wait time ΔT are in a substantially proportional relationship. Therefore, a proportional coefficient k3 of ΔT = k3 × ΔD is determined in advance by experiment, and the information is related to the relationship described above. Information is stored in NVRAM as information. Therefore, in this method, the representative duty value of each roller after the paper feed roller 29 and the transport roller 30 reach the predetermined speed is obtained, ΔD is calculated from the difference therebetween, and the proportionality coefficient that is the relation information is obtained. Using k3, the wait time ΔT is determined from the relationship ΔT = k3 × ΔD.

  The representative duty value can be an average value of a plurality of duty values detected within a preset time.

  In these three methods, the relationship between the information for determining the wait time (ΔT1, ΔL, ΔD, collectively referred to as ΔX) and the wait time ΔT is linear. It is good also as function f == (ΔX). Also in this case, the function f is determined in advance and recorded as related information.

  When the wait time ΔT is determined in this manner and stored in the RAM (step S9), a series of control processing for the transport operation is completed, and thereafter the same processing is repeatedly executed.

  It should be noted that the relationship between the information for determining the wait time (ΔT1, ΔL, ΔD) and the wait time differs depending on the type of the paper 26 and the like. You may make it prepare.

  As described above, in the transport system of the printer 2 according to the present embodiment, the start timing of the transport roller 30 is appropriately delayed based on the behavior during the previous transport operation, that is, based on the immediately preceding situation. Therefore, the conveyance delay at the start of the activation of the paper feed roller 29 can be appropriately eliminated, and the slack of the paper 26 between the paper feed roller 29 and the conveyance roller 30 can be kept constant substantially unchanged during the conveyance operation. It becomes possible. Thereby, even if there is a change in the conveyance status such as the remaining amount of the roll paper 25, the back tension to the conveyance roller 30 can always be eliminated, and the paper 26 can be accurately supplied from the conveyance roller 30 to the printing position. Thus, the print quality can be improved.

  In addition, since the slack set initially does not change substantially, the paper 26 does not come into contact with the members of the transport path due to excessive slack, and it is sufficient that the transport path has a minimum space. There is no need to enlarge the device to eliminate back tension.

  Further, the transport method works more effectively in an apparatus using the roll paper 25 in which the back tension to the paper feed roller 29 is easily changed.

  Further, since the wait time ΔT of the transport roller 30 is determined using each appropriate index, accurate control is possible.

  Furthermore, as described above, more accurate control is possible by preparing and controlling the relationship information for each paper type.

  In this embodiment, the print medium is paper, but the present invention is not limited to this as long as it is a sheet-like medium.

  The protection scope of the present invention is not limited to the above-described embodiment, but covers the invention described in the claims and equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 Host apparatus, 2 Printer, 21 Print control part, 22 Conveyance control part, 23 Head part, 24 Platen, 25 Roll paper, 26 Paper, 27A, B motor, 28A, B Drive roller, 29 Feed roller, 30 Conveyance roller , 31A, B Encoder, 32 Paper discharge roller, 33 Transport path

Claims (8)

An upstream roller that feeds the sheet-like processed medium to the conveyance path, a downstream roller that supplies the sent medium to a processing position, and controls the driving of the upstream roller and the downstream roller to control the medium A control unit that transports the vehicle at a constant speed,
The control unit, based on information indicating the behavior of the upstream roller and the downstream roller until reaching the constant speed during the previous transport operation, the upstream roller and the downstream roller at the start of the transport operation A transfer device characterized by determining the start timing of the. In claim 1,
The determination of the said starting timing is determined so that the starting timing of the said downstream roller may be delayed with respect to the said upstream roller. The conveying apparatus characterized by the above-mentioned. In claim 1 or 2,
The information indicating the behavior up to the constant speed is a time from the start of the upstream roller and the downstream roller to the constant speed. In claim 1 or 2,
The information indicating the behavior until reaching the constant speed is from the start of each of the upstream roller and the downstream roller until the time required from the start of the upstream roller to the constant speed elapses. The transport device is an amount by which the medium to be processed is transported by each of the upstream roller and the downstream roller. In any one of Claims 1 thru | or 4,
Information indicating behavior up to the constant speed and information indicating a relationship between the start timings are stored in advance for each type of the medium to be processed. In any one of Claims 1 thru | or 5,
The conveying apparatus, wherein the medium to be processed is supplied to the upstream roller from a state in which the medium to be processed is held in a roll shape.   A printing apparatus comprising the transport apparatus according to claim 1, wherein the printing apparatus executes printing on the medium to be processed at the processing position. An upstream roller that feeds the sheet-like processed medium to the conveyance path, a downstream roller that supplies the sent medium to a processing position, and controls the driving of the upstream roller and the downstream roller to control the medium A control unit that transports the ink at a constant speed, and a transport method in a transport device comprising:
Based on the information indicating the behavior of the upstream roller and the downstream roller up to the constant speed during the previous transport operation, the control unit starts the transport operation and the upstream roller and the downstream roller. A transfer method characterized by determining the start timing of the.

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