JP2011213452A - Sheet carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of detecting a residual quantity of a roll sheet without receiving influence of volatilization of information.SOLUTION: An image forming device forms an image on a sheet by pulling out the sheet wound on the roll sheet by rotation of a carrier roller. The carrier roller is driven by a motor, and a driving current to the motor is controlled so that the carrier roller rotates in response to a target speed locus. That is, a controller controls the rotation so that the carrier roller operates in response to the target speed locus by adjusting an electric current command value Ir to a driving circuit for driving the motor based on a deviation between the target speed locust and a detecting speed, and achieves carrying control of the sheet corresponding to the target speed locus. The image forming device also determines a sheet residual quantity of a present roll sheet from the electric current command value Ir input to the driving circuit by the controller in response to a table for expressing the corresponding relationship between the electric current command value Ir and the sheet residual quantity x (S130).

Description

  The present invention relates to a sheet conveying apparatus.

  2. Description of the Related Art Conventionally, a sheet conveying apparatus that draws and conveys a sheet from a roll sheet around which the sheet is wound is known. For example, a printer apparatus that pulls out paper from roll paper and conveys the paper to an image forming position by a recording head is known. In this type of apparatus, for example, the remaining amount of roll paper is calculated by subtracting the usage amount from the total amount of roll paper when not in use (see Patent Document 1).

JP 2007-253361 A

  However, the technique for calculating the remaining amount of roll paper by subtracting the usage amount from the total amount of rolls when not in use has the following problems. In other words, with this technique, unless the calculated remaining amount is recorded on a non-volatile recording medium, the remaining amount of roll paper cannot be accurately calculated with the power on / off. Therefore, in this technology, it is necessary to sequentially write the remaining amount to a non-volatile recording medium such as a flash memory. For example, if the latest remaining amount cannot be recorded on the non-volatile recording medium due to a sudden shutdown, for example, There was a problem that the remaining amount could not be calculated accurately.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a technique capable of detecting the remaining amount without being affected by volatilization of information.

  In order to achieve such an object, the sheet conveying apparatus of the present invention includes a holding member that holds a roll sheet on which the sheet is wound, and a sheet drawn from the roll sheet held by the holding member between the opposing member. A conveyance roller that conveys the sheet downstream in the conveyance direction, a motor that rotationally drives the conveyance roller, a motor drive unit that supplies a drive current corresponding to the current command value to the motor, and a current that is input to the motor drive unit By adjusting the command value so that the movement of the conveyance roller follows a predetermined target locus and controlling the motor, the conveyance control unit that conveys the sheet, and the conveyance control unit operates the motor during conveyance of the sheet by the conveyance control unit. And a remaining amount determining unit that determines the remaining amount of the sheet wound around the roll sheet based on a current command value input to the driving unit.

  This sheet conveying apparatus determines the remaining amount of the sheet by utilizing the fact that the tension of the sheet guided from the roll sheet to the conveying roller changes depending on the remaining amount of the sheet. That is, in the sheet conveyance operation using the same target locus, the amount of input current to the motor necessary to realize the target locus changes due to the difference in tension caused by the remaining sheet amount. The sheet conveying apparatus of the present invention uses such a phenomenon to determine the remaining amount of sheets.

  Therefore, according to the present invention, as in the prior art in which the current remaining sheet amount is calculated by subtracting the used amount from the unused sheet remaining amount, the remaining remaining information is obtained by volatilization of the remaining amount information immediately before. It is possible to prevent the amount from being calculated, and the remaining amount can be detected more easily and accurately than in the past.

  The remaining amount determining means is a sheet wound around the roll sheet based on the current command value at a specific time among the current command values input to the motor drive means by the conveyance control means during sheet conveyance by the conveyance control means. The remaining amount can be determined. Examples of the specific time point include a time point after a certain time from the control start time point based on the target locus, a time point when the current command value reaches a peak, and the like.

  In this way, if the remaining amount determination unit is configured to determine the remaining amount of the sheet based on the current command value at a specific time point, it is possible to suppress the influence due to the fluctuation of the current command value due to factors other than the remaining amount of the sheet, The remaining sheet amount can be determined with high accuracy.

  In addition, the sheet conveying apparatus of the present invention can be configured to include a table storage unit that stores a table representing a correspondence relationship between the current command value and the remaining amount. That is, the remaining amount determining means can be configured to determine the remaining amount by referring to this table. If the sheet conveying apparatus is configured as described above, the correspondence between the current command value and the remaining amount is obtained by a test or the like, and this relationship is expressed in a table, so that the remaining amount can be determined with high accuracy. .

  In addition, the remaining amount determination unit can be configured to store the remaining amount determination value in the volatile storage unit. Furthermore, the remaining amount determination means determines the remaining amount based on the current command value at the time of the first sheet conveyance by the conveyance control unit after the sheet conveyance apparatus is turned on, and the determination value of the remaining amount is volatile. It can be configured to store in the storage means. If the sheet conveying apparatus is configured as described above, the remaining amount information can be retained from an early stage after the power is turned on without using an electrically rewritable nonvolatile recording medium.

  In addition, the sheet conveying apparatus subtracts the determination value of the remaining amount by the conveyance amount of the sheet every time the sheet is conveyed by the conveying control unit after the remaining amount is determined by the remaining amount determining unit. The sub-remaining amount determining means for updating the determination value can be provided.

  In addition, the sheet conveying apparatus notifies the user of the remaining amount of the sheet based on the remaining amount determination value by the remaining amount determination unit and / or the remaining amount determination value by the sub remaining amount determination unit. It can be set as the structure provided with. If the sheet conveying apparatus is configured so as to notify the remaining amount, the user can grasp the replenishment timing of the roll sheet, and the convenience of the sheet conveying apparatus can be improved.

1 is a block diagram illustrating a configuration of an image forming apparatus 1. FIG. FIG. 6 is a diagram illustrating a conveyance mode of a sheet by a conveyance roller 33. FIG. 6 is a diagram illustrating a correspondence relationship between a current command value Ir and a remaining sheet amount x. It is a figure showing the structure of table TBL1 for residual amount determination, and message definition table TBL2. It is a figure explaining current command value Ir referred in the case of judgment of sheet remaining amount x. 4 is a flowchart showing remaining amount determination processing executed by main control unit 10.

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the image forming apparatus 1 of this embodiment includes a main control unit 10, a printing unit 20, a sheet conveying unit 30, and a display unit 50. The main control unit 10 performs overall control of the entire apparatus, and includes a CPU 11, a ROM 13, a RAM 15, and an interface 17 that can communicate with an external PC (personal computer) 3. The main control unit 10 realizes a function as an image forming apparatus by the CPU 11 executing a process based on a program recorded in the ROM 13.

  For example, when image data to be printed is input from the external PC 3 through the interface 17, the main control unit 10 drives the printing unit 20 and the sheet conveying unit 30 so as to form an image based on the image data on the sheet. .

  That is, the main control unit 10 causes the printing unit 20 to form a line image on the sheet, and then causes the sheet conveying unit 30 to sub-scan the sheet by a distance De corresponding to the line image formed on the sheet by the printing unit 20. By repeating the process of conveying in the direction, a series of images based on the image data input from the external PC 3 is formed on the sheet through the printing unit 20 and the sheet conveying unit 30.

  More specifically, the printing unit 20 forms a line image having a width corresponding to the distance De in the sub-scanning direction on the sheet in accordance with an instruction from the main control unit 10. For example, the printing unit 20 includes an ink jet recording head and a head transport mechanism (not shown) that can transport the recording head in the main scanning direction, and the main scanning of the recording head according to an instruction from the main control unit 10. By causing the recording head to perform the ink droplet ejection operation while moving in the direction, a line image can be formed on the sheet.

  On the other hand, the sheet conveying unit 30 pulls out a sheet from a roll sheet 31 a connected to the adapter 31 and conveys the sheet to an image forming position by the printing unit 20. The sheet conveyance unit 30 is driven by an adapter 31, a conveyance roller 33, a pinch roller 34 disposed opposite to the conveyance roller 33, a conveyance motor 35 that is a DC motor that rotationally drives the conveyance roller 33, and the conveyance motor 35. A drive circuit 37 that supplies current, a controller 39 that inputs a current command value Ir to the drive circuit 37, an encoder 41 that outputs an encoder signal corresponding to the rotation of the transport roller 33, and an encoder 41. An encoder signal processing unit 43 that detects the rotation amount Q and the rotation speed V of the transport roller 33 based on the encoder signal, and a target command generation unit 45 that inputs the target speed Vr at each time t to the controller 39 are provided.

  The adapter 31 holds the roll sheet 31a rotatably by holding a core material (not shown) in the roll sheet 31a at both ends in the axial direction of the roll sheet 31a. The roll sheet 31a is connected to the adapter 31 so that its axial direction is parallel to the main scanning direction perpendicular to the sub-scanning direction which is the sheet conveying direction.

  On the other hand, the conveyance roller 33 is attached in the housing of the image forming apparatus 1 so that the axial direction thereof is parallel to the main scanning direction like the roll sheet 31a. As shown in FIG. 2, the conveyance roller 33 rotates in response to the power from the conveyance motor 35 while holding the sheet pulled out from the roll sheet 31a together with the pinch roller 34 disposed opposite to the sheet. While pulling out from the sheet 31a, it is conveyed downstream in the sheet conveying direction.

The drive circuit 37 supplies a drive current corresponding to the current command value Ir input from the controller 39 to the carry motor 35 to rotationally drive the carry motor 35.
The controller 39 inputs a deviation E = Vr−V between the rotation speed V of the transport roller 33 input from the encoder signal processing unit 43 and the target speed Vr input from the target command generation unit 45 to a predetermined transfer function. The current command value Ir in the direction in which the deviation E converges to zero is calculated. This is input to the drive circuit 37. In this way, the controller 39 controls the transport motor 35 by adjusting the current command value Ir input to the drive circuit 37 so that the motion of the transport roller 33 follows a preset target speed locus. As a result, the sheet is conveyed downstream in the conveyance direction by a distance De.

  The encoder 41 is a rotary encoder attached to the rotation shaft of the conveyance roller 33 or the rotation shaft of the conveyance motor 35, and outputs an A-phase signal and a B-phase signal as pulsed encoder signals according to the rotation of the conveyance roller 33. Input to the encoder signal processing unit 43.

  The encoder signal processing unit 43 specifies the rotation direction of the conveying roller 33 based on the phase difference between the A phase signal and the B phase signal, and sequentially measures the pulse width in at least one of the A phase signal and the B phase signal, The reciprocal of the width is detected as the rotation speed V of the transport roller 33. Further, based on at least one rising edge of the A-phase signal and the B-phase signal, the rotation amount Q (indirectly, the conveyance amount of the sheet) of the conveyance roller 33 is detected.

Further, the target command generation unit 45 inputs the target speed Vr at each time t to the controller 39 according to the target speed trajectory set in advance through the main control unit 10.
By the way, the main control unit 10 of the present embodiment has a function of forming an image on a sheet through the printing unit 20 and the sheet conveying unit 30, and also based on a current command value Ir input to the drive circuit 37 by the controller 39. Has a function of determining the remaining amount x.

  The principle of determination of the remaining sheet quantity x is as follows. As shown in FIG. 2, when considering a mode in which the sheet wound around the roll sheet is pulled out by the conveying roller 33 and is conveyed, the tension Fl at a point Pl at which a force acts on the sheet from the conveying roller 33. The following relational expression can be obtained by utilizing the relationship in which the sheet tension Fr at the point Pr where the sheet is pulled out from the roll sheet coincides.

モータトルクτは、モータ駆動電流Ｉと比例関係にあり、張力Ｆｌは、モータトルクτと比例関係にあることから、張力Ｆｌは、比例係数Ｋ，Ｋ_tを用いて次式で表すことができる。

The motor torque tau, is proportional to the motor drive current I, tension Fl, since it is proportional to the motor torque tau, tension Fl may represent proportionality coefficients K, with K _t by: .

一方、張力Ｆｒは、ロールシートのイナーシャＪ_r及びロールシートの半径Ｒ_r及びロールシートの回転角θ_rを用いて次式で表すことができる。

On the other hand, the tension Fr can be expressed by the following equation using the roll sheet inertia J _{r, the} roll sheet radius R _r, and the roll sheet rotation angle θ _r .

従って、これらの関係を利用すると、式（１）を導出することができる。

Therefore, using these relationships, the equation (1) can be derived.

Here, the inertia J _r of the roll sheet using a roll sheet of the mass M and the width of the roll sheet (axial width) L, can be expressed by the following equation.

更に、ロールシート質量Ｍ及びロールシート径Ｒ_rは、ロールシートにおけるシート残量ｘを変数に有する次式で表すことができる。ここで、Ａ，Ｂ，Ｃ，Ｄ，Ｅは、ロールシートの構成によって定まる定数である。

Furthermore, the roll sheet mass M and the roll sheet diameter R _r can be expressed by the following equation having the remaining sheet amount x in the roll sheet as a variable. Here, A, B, C, D, and E are constants determined by the configuration of the roll sheet.

また、ロールシートの角加速度については、シート残量ｘを、時間変数ｔを用いて式ｘ＝Ｚ−ｖｔで表現すると共に、式（６）の関係式を用いると、次式で表すことができる。

Further, regarding the angular acceleration of the roll sheet, the remaining sheet amount x can be expressed by the following expression using the expression x = Z−vt using the time variable t and the relational expression (6). it can.

尚、ここでは、時刻ｔ＝０の時点でのシート残量として定数Ｚを形式的に設定する。また、ｖは、ロールシートから引き出されるときのシート速度であり、ａは、ロールシートの回転加速度（周加速度）である。

Here, a constant Z is formally set as the remaining sheet amount at time t = 0. Further, v is a sheet speed when being pulled out from the roll sheet, and a is a rotational acceleration (circumferential acceleration) of the roll sheet.

  Therefore, the following relationship is established between the motor driving current I and the remaining sheet amount x.

式（８）における速度ｖは、搬送ローラ３３の回転速度Ｖに対応し、加速度ａは、搬送ローラ３３の回転加速度ｄＶ／ｄｔに対応する。ここで、搬送ローラ３３がある特定の速度Ｖ及び加速度ｄＶ／ｄｔで回転するときのモータ駆動電流Ｉを参照することを前提とすると、式（８）における速度ｖ及び加速度ａは、定数とみなすことができ、図３にグラフで示すようなモータ駆動電流Ｉとシート残量ｘとの関係が定まる。図３に示すように、モータ駆動電流Ｉは、シート残量ｘに対して単調増加する性質を有する。

The speed v in Expression (8) corresponds to the rotational speed V of the transport roller 33, and the acceleration a corresponds to the rotational acceleration dV / dt of the transport roller 33. Here, assuming that the motor driving current I when the transport roller 33 rotates at a specific speed V and acceleration dV / dt is referred to, the speed v and acceleration a in the equation (8) are regarded as constants. Thus, the relationship between the motor drive current I and the remaining sheet quantity x as shown in the graph of FIG. 3 is determined. As shown in FIG. 3, the motor drive current I has a property of increasing monotonously with respect to the remaining sheet amount x.

  In the present exemplary embodiment, the image forming apparatus 1 is configured so as to determine the remaining sheet amount x using such a relationship. However, in this embodiment, the current command value Ir is assumed under the assumption that the current command value Ir input by the controller 39 to the drive circuit 37 and the drive current I supplied from the drive circuit 37 to the transport motor 35 match. The sheet remaining amount x is determined from Ir.

  That is, the relationship between the current command value Ir and the sheet remaining amount x when the conveying roller 33 takes a specific speed V and acceleration dV / dt is obtained by a test or desk calculation, and the current command value Ir and the sheet remaining amount x are calculated. Are recorded in the ROM 13 as a table. In the main control unit 10, the remaining sheet amount is obtained from the controller 39 by acquiring the current command value Ir when the conveying roller 33 takes the specific speed V and acceleration dV / dt and recording it in the ROM 13. For example, x is determined.

  Specifically, the image forming apparatus 1 of the present embodiment has a remaining amount determination table TBL1 as shown in FIG. This remaining amount determination table TBL1 has information on the remaining sheet amount x corresponding to the current command value Ir in this section for each section obtained by subdividing the range in which the current command value Ir can be taken into a plurality of sections. The width of each section can be determined in consideration of the remaining sheet determination error, the table data size, and the like.

  In the sheet conveyance process by the sheet conveyance unit 30, the conveyance roller 33 accelerates from a stationary state to reach a certain speed, and then decelerates according to the target speed locus. For this reason, in this embodiment, conveyance is performed at this speed Vr and acceleration dVr / dt on the basis of the target speed Vr and target acceleration dVr / dt at the point of maximum acceleration PM (see FIG. 5) in the target speed trajectory of the acceleration section. A relationship between the current command value Ir when the roller 33 rotates and the sheet remaining amount x is obtained, and a remaining amount determination table TBL1 is generated.

  As described above, the relationship between the current command value Ir and the remaining sheet amount x is obtained based on the target speed Vr and the target acceleration dVr / dt at the point of maximum acceleration PM, and the remaining amount determination table TBL1 is generated. There is a proportional relationship between the acceleration and the current command value Ir, and the current command value Ir takes a maximum value (maximum value) Imax at the maximum acceleration point PM in the target speed trajectory as shown in FIG. is there. If the current command value Ir takes the maximum value (maximum value), the determination error of the remaining sheet amount x can be suppressed, and the remaining sheet amount x can be accurately determined. When determining the remaining sheet amount x, the current command value Ir at the point of maximum acceleration PM can be accurately identified by detecting the maximum value (maximum value) Imax of the current command value Ir. For this reason, in the present embodiment, the relationship between the current command value Ir and the remaining sheet amount x is obtained based on the target speed Vr and the target acceleration dVr / dt at the maximum acceleration point PM in the target speed trajectory in the acceleration section. Using this relationship, the remaining amount determination table TBL1 is generated.

  As shown in FIG. 4, in this embodiment, a message definition table TBL <b> 2 in which a message to be displayed on the display unit 50 with respect to the remaining sheet amount x is defined in the ROM 13. In this message definition table TBL2, message information indicating the remaining amount level of the sheet to be displayed on the display unit 50 is associated with each section obtained by dividing the range in which the sheet remaining amount x can be taken into several sections. It is.

  In the example shown in FIG. 4, messages to be displayed on the display unit 50 are determined in four stages according to the remaining sheet amount x. The image forming apparatus 1 according to the present embodiment switches the message to be displayed on the display unit 50 according to the remaining sheet amount x according to the message definition table TBL2. As a result, the user is notified of the remaining sheet capacity x.

  Subsequently, the remaining amount determination process executed in parallel when the main control unit 10 starts the control of the conveyance motor 35 (the sheet conveyance operation for the distance De) according to the target speed locus in the sheet conveyance unit 30 will be described with reference to FIG. Will be described.

  When the remaining amount determination process shown in FIG. 6 is started, the main control unit 10 determines whether or not the current control process of the transport motor 35 by the sheet transport unit 30 is the first control process after the image forming apparatus 1 is turned on. (S110), and if it is determined that the process is the first control process (Yes in S110), information on the current command value Ir input from the controller 39 to the drive circuit 37 is sequentially acquired to obtain a current command in the acceleration section. The maximum value Imax of the value Ir is detected, and the rotation amount of the conveyance roller 33 at the time when the current command value Ir reaches the maximum value Imax based on the rotation amount Q of the conveyance roller 33 input from the encoder signal processing unit 43. Q0 is specified (S120). The determination as to whether or not it is the first control process is based on whether or not the remaining sheet quantity xm is stored in the RAM 15. That is, if the sheet remaining amount xm is not stored in the RAM 15, it is determined that the control process is the first time, and if the sheet remaining amount xm is stored in the RAM 15, it is determined that the control process is performed after the first time.

  Further, based on the detected maximum value Imax of the current command value Ir, the remaining sheet amount xn at the time when the maximum value Imax is detected is determined with reference to the remaining amount determination table TBL1 (S130). That is, the sheet remaining amount x associated with the section of the current command value Ir subdivided in the remaining amount determination table TBL1 and to which the maximum value Imax detected in S120 belongs is determined as the sheet remaining amount xn. To do. Since the target speed trajectory varies depending on the sheet conveyance conditions, a plurality of remaining amount determination tables TBL1 are set according to the sheet conveyance conditions.

  Then, the determination value (sheet remaining amount xn) is stored and held in the RAM 15 as the sheet remaining amount xm (S140). Further, based on the sheet remaining amount xm, a message to be displayed on the display unit 50 is specified with reference to the message definition table TBL2 stored in the ROM 13, and this message is displayed on the display unit 50 (S150). That is, in the message definition table TBL2, the message associated with the section to which the remaining sheet quantity xm belongs is selected as the message to be displayed, and this message is displayed on the display unit 50. However, in S150, the message corresponding to the remaining sheet quantity xm is displayed on the display unit 50 by updating the already displayed message. Thereafter, the process proceeds to S160.

  In S160, the conveyance motor 35 is decelerated and stopped, waits until the control process of the conveyance motor 35 is once completed, and the conveyance roller 33 input from the encoder signal processing unit 43 when the control of the conveyance motor 35 is once completed. Based on the rotation amount Q1, the sheet conveyance amount δ = Q1-Q0 from the time point when the maximum value Imax is detected to the present time is calculated. Thereafter, the remaining sheet amount xm stored in the RAM 15 is updated to a value obtained by subtracting the sheet conveyance amount δ (S180). Further, based on the updated sheet remaining amount xm, a message to be displayed on the display unit 50 is specified with reference to the message definition table TBL2 stored in the ROM 13, and this message is displayed on the display unit 50 (S190). . Thereafter, the remaining amount determination process ends.

  On the other hand, when the main control unit 10 determines that the control process of the transport motor 35 by the current sheet transport unit 30 is not the first control process after power-on of the image forming apparatus 1 (No in S110), the process proceeds to S170. From the rotation amount Q0 of the conveyance roller 33 input from the encoder signal processing unit 43 at the start of the control process and the rotation amount Q1 of the conveyance roller 33 at the end of the control process, the sheet conveyance amount δ = Q1-Q0 is calculated (S170).

  Thereafter, the remaining sheet quantity xm stored in the RAM 15 is updated to a value obtained by subtracting the sheet conveyance amount δ calculated in S170 (S180), and a message to be displayed on the display unit 50 based on the remaining sheet quantity xm is displayed as a message. The message is specified from the definition table TBL2, and this message is displayed on the display unit 50 (S190). Thereafter, the remaining amount determination process ends.

  The configuration of the image forming apparatus 1 according to the present exemplary embodiment has been described above. According to the present exemplary embodiment, the remaining sheet amount x is determined based on the current command value Ir in the first control process after the power is turned on for the image forming apparatus 1. This is stored and stored in the RAM 15, and thereafter, the remaining sheet quantity xm is updated in accordance with the sheet conveyance amount δ.

  In the determination operation of the remaining sheet amount x based on the current command value Ir, the remaining sheet amount x can be accurately identified even if the information on the sheet usage amount since the unused state is not retained. Therefore, according to the present embodiment, if the information on the amount of used sheets from the unused time is lost, the conventional problem that the subsequent operation of detecting the remaining amount of sheets cannot be solved, and the convenience is high. The image forming apparatus 1 can be configured.

  By the way, the correspondence between the above-described embodiment and “Claims” is as follows. That is, the holding member described in “Claims” corresponds to the adapter 31 included in the image forming apparatus 1, the motor driving unit corresponds to the driving circuit 37, and the conveyance control unit corresponds to the controller 39. Further, the remaining amount determining means is realized by remaining amount determination processing executed by the main control unit 10. In particular, the operation in which the remaining amount determination unit stores the remaining amount determination value in the volatile storage unit corresponds to the operation in which the remaining sheet amount xm is stored in the RAM 15. The table storage means corresponds to the storage area of the remaining amount determination table TBL1 in the RAM 15. In addition, the sub remaining amount determination means corresponds to the processing of S180 in the remaining amount determination processing. Further, the notification means corresponds to S150 and S190 processing in the display unit 50 and the remaining amount determination processing.

  Further, the present invention is not limited to the above-described embodiments, and can take various forms. For example, in the above-described embodiment, the determination operation of the remaining sheet amount x based on the current command value Ir is not performed except for the first control process after the power is turned on, but the image forming apparatus 1 performs each control process other than the first control process. In this case, the determination may be made for the remaining sheet quantity x based on the current command value Ir. In other words, the image forming apparatus 1 may be configured to omit steps S110 and S170 in the remaining amount determination process and always execute the processes after S120.

  If the remaining sheet amount xm stored in the RAM 15 in the previous conveyance is equal to or greater than a predetermined amount, the remaining sheet amount x is determined based on the current value Ir. The remaining sheet amount x may be calculated based on the amount.

  In addition, after the message indicating the remaining amount level corresponding to the remaining sheet amount xm is displayed in S150, it is not necessary to update the remaining sheet amount xm by the rotation amount δ of the conveying roller 33. That is, in the operation for determining the remaining sheet amount x based on the current command value Ir, the processing of S160 to S190 is omitted, and only the remaining amount level is determined based on the remaining sheet amount x at the time corresponding to Imax. good.

  Further, in the above-described embodiment, the maximum value Imax of the current command value Ir is detected, and the operation for determining the remaining sheet amount x is performed based on the detected current command value Ir. The remaining sheet quantity x may be determined based on the current command value Ir at the set time. Since the transport roller 33 is controlled to follow a predetermined driving locus, the time point when the specific speed V and acceleration dV / dt are controlled is always the same as long as it is controlled using the same driving locus. Therefore, it is possible to determine the remaining sheet quantity x based on the current command value Ir at a specific time set in advance from the start of driving. The conveyance roller 33 may be controlled to follow a target position locus or a target acceleration locus instead of the target velocity locus.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 10 ... Main control unit, 11 ... CPU, 13 ... ROM, 15 ... RAM, 17 ... Interface, 20 ... Printing unit, 30 ... Sheet conveyance unit, 31 ... Adapter, 31a ... Roll sheet, 33 ... Conveyance roller, 34 ... Pinch roller, 35 ... Conveyance motor, 37 ... Drive circuit, 39 ... Controller, 41 ... Encoder, 43 ... Encoder signal processing unit, 45 ... Target command generation unit, 50 ... Display unit, TBL1 ... Remaining amount Judgment table, TBL2 ... Message definition table

Claims (7)

A holding member for holding a roll sheet on which the sheet is wound;
A conveyance roller for nipping the sheet drawn from the roll sheet held by the holding member between the opposite member and conveying the sheet downstream in the conveyance direction;
A motor that rotationally drives the transport roller;
Motor driving means for supplying a driving current corresponding to a current command value to the motor;
A conveyance control means for conveying the sheet by adjusting the current command value input to the motor driving means so that the movement of the conveyance roller follows a predetermined target locus, and controlling the motor;
A remaining amount determination unit that determines a remaining amount of the sheet wound around the roll sheet based on a current command value input to the motor driving unit by the conveyance control unit during conveyance of the sheet by the conveyance control unit;
A sheet conveying apparatus comprising: The remaining amount determining means is based on the current command value at a specific point of time among the current command values input to the motor driving means by the conveyance control means when the sheet is conveyed by the conveyance control means. The sheet conveying apparatus according to claim 1, wherein the remaining amount of the sheet wound around the sheet is determined. Table storage means for storing a table representing a correspondence relationship between the current command value and the remaining amount;
The sheet conveying apparatus according to claim 1, wherein the remaining amount determining unit determines the remaining amount with reference to the table. With volatile storage means,
The remaining amount determination unit is configured to store the determination value of the remaining amount in the volatile storage unit, and after the power of the sheet conveying apparatus is turned on, the current command at the first sheet conveyance by the conveyance control unit The sheet conveyance according to any one of claims 1 to 3, wherein the remaining amount is determined based on a value, and the determination value of the remaining amount is stored in the volatile storage unit. apparatus. After the determination of the remaining amount by the remaining amount determination unit, each time the sheet is conveyed by the conveyance control unit, the determination value of the remaining amount is obtained by subtracting the determination value of the remaining amount by the conveyance amount of the sheet. The sheet conveying apparatus according to claim 1, further comprising: a sub remaining amount determining unit that updates the value. 6. The apparatus according to claim 1, further comprising a notification unit configured to notify a user of the remaining amount of the sheet based on a determination value of the remaining amount by the remaining amount determination unit. Sheet transport device. The sheet conveying apparatus according to claim 5, further comprising a notifying unit that notifies the user of the remaining amount of the sheet based on the updated remaining amount determination value by the sub remaining amount determining unit.

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