JP5062044B2 - Sheet conveying apparatus and image recording apparatus - Google Patents

Description

  The present invention relates to a sheet conveying apparatus that conveys the sheet by rotating a roller provided at the tip of a rotatable arm in contact with the sheet, and an image recording apparatus equipped with the sheet conveying apparatus About.

An image recording apparatus such as an ink jet printer includes a sheet conveying apparatus that feeds a recording sheet stored in a sheet feeding tray to a conveying path by the rotational force of a roller. When the roller rotates in contact with the recording paper on the paper feed tray, the rotational force of the roller is transmitted to the recording paper, and the recording paper is fed from the paper feed tray to the conveyance path. In this type of sheet conveying apparatus, the roller slips against the recording paper on the paper feed tray due to roller wear or dirt attached to the roller, which causes the recording paper from the paper feeding tray to the conveyance path. May cause a paper feed error such as not being fed . Techniques for preventing the occurrence of such a paper feed error are disclosed in Patent Document 1 and Patent Document 2.

The paper feed device described in Patent Document 1 includes a pickup roller that feeds recording paper from a paper feed tray to a conveyance path. The pick-up roller is formed in a half-moon shape in which a part of a circular cross section is cut out by a straight line. The pickup roller is rotatably disposed above the paper feed tray. A rotation plate that is biased upward by a spring is provided inside the paper feed tray. A recording sheet is placed on the rotating plate. When the recording paper feeding operation is started, the driving force from the motor is transmitted to the pickup roller, and the pickup roller rotates. When the arc portion of the pickup roller is positioned below the rotation shaft, the pickup roller is pressed against the recording sheet on the sheet feeding tray. Then, the rotational force of the pickup roller is transmitted to the uppermost recording sheet on the sheet feeding tray. As a result, the recording paper is fed from the paper feed tray to the conveyance path. A sensor for detecting the presence / absence of a recording sheet is disposed at a predetermined position in the conveyance path. In this paper feeding device, when the recording paper is not detected by the sensor until a predetermined time has elapsed after the feeding operation by the pickup roller is started, the pickup roller slips against the recording paper and the recording paper It is determined that a paper feed error has occurred. Then, a recording paper refeeding operation is executed. Specifically, the pickup roller is rotated at a lower rotational speed than before the paper feeding error occurs. As a result, the contact time of the peripheral surface of the pickup roller with respect to the recording paper on the paper feed tray becomes longer, and the force with which the pickup roller feeds the recording paper increases. As a result, the probability that the recording paper can be fed out from the paper feed tray is increased, and a paper feed error is prevented from occurring in the refeed operation.

  Japanese Patent Application Laid-Open No. 2004-228688 describes changing the rotation speed of a pulse motor that rotates a roller in a refeeding operation of a recording sheet after a feeding error occurs. In the recording apparatus according to the first embodiment of Patent Document 2, a refeed operation (retry) after a paper feed error is performed in order to prevent a paper feed error due to a roller slip or the like from occurring repeatedly. At this time, the rotational speed of the pulse motor is set to be lower than usual. On the other hand, in the recording apparatus according to the second embodiment of Patent Document 2, a refeed operation (retry) is performed for the purpose of minimizing the time from the start of the paper feed operation to the completion of image recording on the recording paper. In contrast to the first embodiment, the rotational speed of the pulse motor is set larger than usual.

JP 2003-31867 A JP-A-8-169632

  However, in a sheet conveying apparatus in which a roller is rotatably provided on the tip end side of an arm that can be rotated toward and away from the paper feed tray, the rotation speed of the roller is set to be higher than usual in a refeed operation If it is made smaller, the vertical drag of the roller is lowered. Therefore, the maximum static frictional force between the recording paper and the roller is reduced, and the roller is less likely to bite against the recording paper. Therefore, in the sheet conveying apparatus, if the rotation speed of the roller is made smaller than usual during the re-feeding operation, the roller easily slips and a sheet feeding error reoccurs. On the other hand, in the sheet conveying apparatus, even if the rotational speed of the roller is larger than usual during the refeeding operation, if the acceleration until reaching the set speed is the same, the roller for the recording paper Will slip. Once the roller slips against the recording paper, even if the roller reaches a speed higher than the normal speed, the friction force generated between the roller and the recording paper is a dynamic friction force smaller than the maximum static friction force. For this reason, the roller does not bite the recording paper. For this reason, even if the rotational speed of the roller is increased more than usual during the refeed operation, the roller slips with respect to the recording paper, which causes a problem that the paper feed error reoccurs. Each of the above problems can also occur in an automatic document feeder (ADF) having a mechanism in which a roller is supported by the arm or an image reading device (scanner) including the automatic document feeder. .

  The present invention has been made in view of the above-described problems, and in a sheet conveying apparatus that conveys a sheet by means of a roller rotatably provided on the distal end side of a rotatable arm, after sheet feeding has failed. An object of the present invention is to provide means capable of preventing the reoccurrence of a feeding error during the refeeding operation.

(1) In order to achieve the above object, the present invention is configured as a sheet conveying apparatus including a placement unit, a roller, an arm, a control unit, and a determination unit. The placement unit is for placing at least one sheet. The roller is rotatably provided on the tip side of the arm. This roller feeds the sheet from the placement section to the conveyance path. The arm is disposed above the mounting portion. This arm is rotatably supporting the roller, around the upstream side of the feeding direction of the sheet than the roller, the roller is configured to rotatably seat the direction toward or away from. The control means accelerates the roller in a stationary state and then rotates the roller at a preset target speed. The determination means determines whether or not the roller has failed to feed the sheet on the placement section during the control by the control means. For example, the determination unit determines whether the sheet feeding has failed based on an output signal of a sensor provided in a conveyance path or the like. In the sheet conveying apparatus of the present invention, the control unit is configured to perform the first control mode in which the roller is accelerated at a first acceleration until the determination unit determines that the roller has failed to feed the sheet. Control the rotation of the roller. Then, on the condition that the determination unit determines that the roller has failed to feed the sheet, the roller is stopped, and then the roller is accelerated at a second acceleration larger than the first acceleration. The rotation of the roller is controlled in the two control mode.

For example, the arm is rotatably provided on the frame of the sheet conveying apparatus. The roller is rotatably supported on the tip side of the arm. The arm is biased toward the mounting portion by its own weight or by receiving an elastic force from a spring or the like. For this reason, the roller comes into contact with the uppermost sheet in the placement section with an appropriate pressure. The control means controls the rotation of the roller by driving a motor or the like connected to the roller. When the roller is rotated by the control means, the uppermost sheet placed on the placement unit is sent out from the placement unit under the rotational force of the roller and is fed to the conveyance path.

  Until the determination unit determines that the roller has failed to feed the sheet, the control unit performs control in the first control mode in which the roller is accelerated at the first acceleration. Then, on the condition that the determination unit determines that the roller has failed to feed the sheet, the control unit accelerates the roller at a second acceleration larger than the first acceleration. To control.

  Accordingly, since the acceleration of the roller is larger when the roller is controlled in the second control mode than when the roller is controlled in the first control mode, the roller and the uppermost sheet are stationary. The frictional force increases. Therefore, in the roller rotation control in the first control mode, since the acceleration of the roller is insufficient, the biting on the uppermost sheet becomes worse, and the feeding fails because the roller slips on the sheet. However, in the rotation control of the roller in the second control mode, since the acceleration of the roller increases, the biting of the roller with respect to the uppermost sheet is improved, and the problem that the roller slips is solved.

  (2) Further, the present invention is configured as a sheet conveying apparatus including a placement unit, an arm, a roller, a control unit, and a determination unit. The placement unit is for placing at least one sheet. The arm is disposed above the mounting portion. The arm is configured to be rotatable in a direction in which the arm is in contact with or separated from the mounting portion. The roller is rotatably provided on the tip side of the arm. The roller is in contact with the sheet placed on the placement unit in a stationary state, and supplies the sheet from the placement unit to the conveyance path. The control means accelerates the roller in a stationary state and then rotates the roller at a preset target speed. The determination means determines whether or not the roller has failed to feed the sheet on the placement section during the control by the control means. For example, the determination unit determines whether the sheet feeding has failed based on an output signal of a sensor provided in a conveyance path or the like. In the sheet conveying apparatus of the present invention, the control unit is configured to perform the first control mode in which the roller is accelerated at a first acceleration until the determination unit determines that the roller has failed to feed the sheet. Control the rotation of the roller. Then, on the condition that the determination unit determines that the roller has failed to feed the sheet, the roller is stopped, and then the roller is accelerated at a second acceleration larger than the first acceleration. The rotation of the roller is controlled in the two control mode.

(3) The control means accelerates the roller to the target speed after elapse of a preset time after the acceleration control of the roller is started. In this case, the control means switches from the first control mode to the second control mode by changing the set value of the target speed from the first speed to a second speed larger than the first speed.

  Since it is configured in this way, the control by the control means can be changed from the first control mode to the second control mode by a simple method of changing the set value of the target speed. Further, in any of the first control mode and the second control mode, a certain set time is secured as the time required for the acceleration of the roller. That is, in any control mode, a certain time for the roller to bite into the sheet is secured.

(4) The control means accelerates the roller to the target speed after a preset set time has elapsed since the start of acceleration control of the roller, and sets the set value of the set time to a first set time. May be switched from the first control mode to the second control mode by changing to a second set time shorter than the first set time.

  Since it is configured in this way, the control by the control means can be changed from the first control mode to the second control mode by a simple method of changing the set value of the set time. Moreover, it is possible to control the roller at a constant target speed in any of the first control mode and the second control mode. In the second control mode, acceleration increases, biting on the seat is improved, and time until the target speed is reached can be shortened.

(5) The sheet conveying apparatus of the present invention includes a recognition unit that recognizes the type of the sheet placed on the placement unit. In this case, the control means determines that the roller has failed to feed the sheet by the determination means, and recognizes that the sheet of the placement section is the first sheet having a predetermined thickness by the recognition means. On the condition, the roller is stopped, and then the rotation of the roller is controlled in the second control mode. The condition is that the determination unit determines that the roller has failed to feed the sheet, and the recognition unit recognizes that the sheet of the placement unit is a second sheet thicker than the first sheet. In addition, after the roller is stopped , the rotation of the roller is controlled in a third control mode in which the roller is accelerated at a third acceleration larger than the second acceleration.

  The force with which the roller tries to bite the sheet (hereinafter referred to as “biting force”) varies depending on the type of the sheet. For example, when the sheet is extremely thin like tracing paper, if the acceleration is increased excessively to increase the biting force, the sheet may be damaged by the rotational force received from the roller. On the other hand, in the case of a relatively thick sheet such as glossy paper, even if the acceleration is slightly increased, the sheet is not damaged by the rotational force received from the roller. Therefore, in the sheet conveying apparatus of the present invention, when the first sheet thinner than the second sheet is fed again after the sheet feeding has failed, the acceleration is suitable for the first sheet (for example, the second acceleration). When the roller is controlled in the set second control mode and the second sheet thicker than the first sheet is fed again, the third control set to an acceleration suitable for the second sheet (for example, the third acceleration). The roller is controlled by the mode. As a result, the sheet is fed at the optimum acceleration for the type.

  (6) The sheet conveying apparatus of the present invention is provided on the downstream side in the sheet conveying direction with respect to the sheet placed on the placement unit, and separates the sheets stacked on the placement unit A member is provided. The control means sets the target speed to the first target speed and rotates the roller until the downstream end of the sheet on the placement section passes through the separating member, and rotates the roller on the downstream side. It is preferable to control the rotation of the roller in a fourth control mode in which the target speed is set to a second target speed larger than the first target speed after the end portion has passed through the separation member and the roller is rotated. .

  When the leading edge of the uppermost sheet in the placement section passes through the separating member, the leading edge of the sheet is rolled by the separating member, and the uppermost sheet and the sheet immediately below it are separated. Therefore, the frictional force that the uppermost sheet receives from the sheet immediately below is lower than the state before the leading edge of the sheet passes through the separation member. For this reason, after the leading edge of the sheet has passed through the separation member, conveyance control suitable for the conveyance path after the separation member may be performed. As described above, after the leading edge of the sheet passes through the separation member, the frictional force applied to the sheet decreases. For this reason, it is preferable to suppress the biting force of the roller on the sheet and instead increase the sheet feeding speed to shorten the time required for sheet conveyance. In the sheet conveying apparatus, the control unit controls the rotation of the roller in the fourth control mode as described above. Therefore, after the leading edge of the sheet passes through the separation member, the roller is rotated so that the second target speed is higher than the first target speed. Thereby, the conveyance speed of the sheet after passing the separation member is increased, and the time required for conveyance of the sheet is shortened.

(7) Further, an image recording apparatus according to the present invention includes the above-described sheet conveyance device and a recording unit that records an image on the sheet fed to the conveyance path by the roller. Even with such an image recording apparatus, the same effects as those of the sheet conveying apparatus described above can be obtained.

  According to the present invention, in a sheet conveying apparatus that conveys a sheet by a roller rotatably provided on the tip side of a rotatable arm, a feeding error at the time of refeeding operation after the sheet feeding has failed. It is possible to prevent the recurrence of

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as appropriate. In addition, this embodiment is only an example of this invention and can be suitably changed in the range which does not change the summary of this invention.

[Explanation of drawings]
FIG. 1 is an external perspective view of a multifunction machine 10 according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the internal structure of the printer unit 11. FIG. 3 is a block diagram illustrating the configuration of the control unit 100. 4 to 6 are flowcharts showing an example of a rotation control processing procedure performed by the control unit 100 when the printer unit 11 feeds a recording sheet. 7 and 8 are graphs illustrating the change in the rotation speed of the paper feed roller 25. FIG. FIG. 9 is a graph illustrating the change in the rotation speed when the paper feed roller 25 is accelerated in a modification of the present embodiment. In FIG. 2, a part of the paper feed tray 20 and a part of the paper discharge tray 21 are omitted.

[Schematic configuration of MFP 10]
As shown in FIG. 1, the multifunction machine 10 is configured in a substantially rectangular parallelepiped shape that is wider in the width direction 122 and the depth direction 123 than in the height direction 121. The multifunction machine 10 is integrally provided with a printer unit 11 and a scanner unit 12, and has a print function, a scan function, a copy function, and a facsimile function. The printer unit 11 corresponds to the image recording apparatus according to the present invention. The multifunction machine 10 does not necessarily have the scanner unit 12, and the image recording apparatus according to the present invention may be implemented as a single-function printer that does not have a scanner function or a copy function.

  A printer unit 11 is provided in the lower part of the multifunction machine 10. The printer unit 11 is mainly connected to an external information device (not shown) such as a computer. The printer unit 11 uses the recording paper 50 (an example of the sheet of the present invention, FIG. 2) based on the recording data received from the external information device and the recording data generated based on the image data of the original read by the scanner unit 12. Image).

  A scanner unit 12 is provided in the upper part of the multifunction machine 10. The scanner unit 12 is configured such that the document cover 15 can be opened and closed with respect to the document table 19 via a hinge (not shown) on the back side. The document table 19 functions as a so-called flatbed scanner. Although not shown in the drawing, a contact glass is provided on the upper surface of the document table 19. The contact glass is a transparent plate member on which a document is placed. A line sensor (not shown) extending in the depth direction 123 is disposed inside the document table 19. This line sensor is configured to be able to reciprocate in the width direction 122. An image of the original placed on the contact glass is read by the line sensor.

  The document cover 15 functions as a top plate of the multifunction machine 10. The document cover 15 is provided with an ADF 29. The ADF 29 conveys the document placed on the document tray 30 to the document discharge tray 31 via a conveyance path (not shown). In the process of transporting the document by the ADF 29, the document passes over a contact glass (not shown). At that time, the image of the original is read by the line sensor arranged below the contact glass. The document from which the image has been read is held on both sides of the document discharge tray 31 and is held in a state separated from the document on the document tray 30.

  As shown in FIG. 1, a paper feed cassette 33 is disposed inside the printer unit 11. The paper feed cassette 33 includes a paper feed tray 20 (an example of a placement unit of the present invention) and a paper discharge tray 21. The paper feed tray 20 and the paper discharge tray 21 are arranged in two upper and lower stages with the paper discharge tray 21 as the upper side of the paper feed tray 20. An opening 13 is formed on the front side of the printer unit 11. The paper feed cassette 33 is inserted into and removed from the printer unit 11 through the opening 13. Recording paper 50 (hereinafter simply referred to as “recording paper”) used for image recording is stored in the paper feed tray 20 in a stacked state (see FIG. 2). The recording paper in the paper feed tray 20 is supplied to the inside of the printer unit 11 one by one. The recording sheet is discharged onto the discharge tray 21 after an image is recorded by a recording unit 24 (an example of the recording unit of the present invention, see FIG. 2) provided inside the printer unit 11.

  An operation panel 14 is provided at the upper front of the multifunction machine 10. The operation panel 14 is provided with a display for displaying various types of information and buttons for receiving input of information. The multifunction machine 10 operates based on instruction information input from the operation panel 14. In the present embodiment, the type information of the recording paper placed on the paper feed tray 20 can be input via the operation panel 14. The input type information is stored in the RAM 103 of the control unit 100 described later. When the multifunction device 10 is connected to an external information device, the multifunction device 10 also operates based on instruction information transmitted from the external information device through a printer driver, a scanner driver, or the like. Of course, the type information may be input from an external information device.

[Printer 11]
As shown in FIG. 2, the printer unit 11 is roughly divided into a paper feed tray 20, a supply unit 32, a conveyance path 23 (an example of the conveyance path of the present invention), a registration sensor 71 (a part of the detection unit of the present invention). ), A conveyance roller pair 59, a discharge roller pair 64, and a paper discharge tray 21. In the present embodiment, the sheet conveying apparatus of the present invention includes the paper feed tray 20, the supply unit 32, the conveyance path 23, the registration sensor 71, the conveyance roller pair 59, the discharge roller pair 64, and a control unit 100 (see FIG. 3) described later. Is configured.

[Paper Tray 20]
The paper feed tray 20 is loaded with a rectangular recording paper of a standard size. The paper feed tray 20 can accommodate recording paper of various sizes such as A4 size, B5 size, and postcard size. The types of recording paper stored in the paper feed tray 20 include plain paper (an example of the first sheet of the present invention), glossy paper (an example of the second sheet of the present invention), and inkjet paper (the second sheet of the present invention). Example). In addition, the 1st sheet | seat and 2nd sheet | seat of this invention will not be limited to the above-mentioned thing, if a 2nd sheet | seat is thicker than a 1st sheet | seat. For example, the first sheet of the present invention may be inkjet paper, and the second sheet of the present invention may be glossy paper that is thicker than inkjet paper.

  The paper discharge tray 21 has a plate shape that is shorter in the depth direction 123 than the paper feed tray 20. The paper discharge tray 21 is provided on the front side of the multifunction machine 10. For this reason, in the paper feed tray 20, the front side of the multifunction machine 10 is covered with the paper discharge tray 21, and a part of the rear side of the multifunction machine 10 is opened. A supply unit 32 to be described later is disposed in the opening portion of the paper feed tray 21.

  The transport path 23 is a path through which the recording paper supplied from the paper feed tray 20 is transported. As shown in FIG. 2, the conveyance path 23 is directed upward from an inclined plate 22 described later, then bent toward the front side of the multifunction machine 10, and linearly extends to the paper discharge tray 21 through the recording unit 24. It is installed. The conveyance path 23 is partitioned by guide members (not shown) that face each other at a predetermined interval except for the place where the recording unit 24 is disposed.

  The conveyance path 23 can be divided into three sections, a first section L1, a second section L2, and a third section L3. The first section L1 is a range from the inclined plate 22 of the paper feed tray 20 to a position P0 set immediately above the inclined plate 22. The second section L2 is a range from the position P0 to the position P1 where the registration sensor 71 is disposed. The third section L3 is a range from the position P1 to the conveyance roller pair 59. Note that the position P0 is a position where it is estimated that the leading end 45 of the recording sheet will be surely separated from the recording sheet below it by a separation piece 35 (an example of the separation member of the present invention) described later. This position P0 can be identified, for example, by repeatedly experimenting with the feeding operation of the recording paper by the paper feed roller 25. Further, the position P1 is a position set on the upstream side in the transport direction with respect to the transport roller pair 59. This position P1 is disposed at a position close to the conveyance roller pair 59.

  The inclined plate 22 is provided on the back side (the right side in FIG. 2) of the paper feed tray 20. The inclined plate 22 is inclined so as to fall to the back side of the apparatus (the right side in FIG. 2). When the paper feed tray 20 is attached to the printer unit 11, the inclined plate 22 is disposed below the conveyance path 23. In other words, the inclined plate 22 is disposed between the recording paper placed on the paper feed tray 20 and the transport path 23. That is, the inclined plate 22 is provided on the downstream side of the recording sheet on the sheet feeding tray 20 in the conveying direction of the recording sheet. The inclined plate 22 is provided with a separation piece 35 that separates recording sheets one by one in cooperation with a feed roller 25 (an example of the roller of the present invention) described later. The separation piece 35 includes a plurality of teeth protruding from the inner surface of the inclined plate 22, and is arranged vertically along the conveying direction on the inner surface of the inclined plate 22. When a bundle of recording sheets fed by a sheet feeding roller 25 described later comes into contact with the separation piece 35, the recording sheet is rolled by the separation piece 35. Thereby, the recording paper is separated.

[Arm 26, paper feed roller 25]
The supply unit 32 is disposed on the upper side of the paper feed tray 20. The supply unit 32 supplies recording paper from the paper feed tray 20 to the transport path 23. The supply unit 32 includes a paper feed roller 25, an arm 26 (an example of the arm of the present invention), and a shaft 28. The shaft 28 is supported by a frame (not shown) of the printer unit 11 on the upper side of the paper feed tray 20. The base end portion of the arm 26 is rotatably supported by the shaft 28. For this reason, the arm 26 can rotate in a direction in which the arm 26 contacts and separates from the paper feed tray 20 around the shaft 28. The paper feed roller 25 is rotatably provided on the tip side of the arm 26. The arm 26 is urged to rotate toward the paper feed tray 20 by its own weight or receiving an elastic force from a spring or the like. For this reason, when the paper feed cassette 33 is mounted on the printer unit 11, the paper feed roller 25 contacts the uppermost recording paper in the paper feed tray 20 with an appropriate pressure.

  The arm 26 is provided with a power transmission mechanism (not shown) for transmitting the driving force of an ASF (Auto Sheet Feed) motor 84 (see FIG. 3) to the paper feed roller 25. The ASF motor 84 is rotated by being controlled by a control unit 100 (see FIG. 3) described later, and the driving force is transmitted to the sheet feeding roller 25 via the shaft 28 and the power transmission mechanism of the arm 26. As a result, the paper feed roller 25 rotates at a rotation speed corresponding to the rotation control of the control unit 100. In this embodiment, the rotation of the paper feed roller 25 is controlled by the control unit 100 so that the rotation speed (number of rotations) of the paper feed roller 25 varies depending on the position of the leading edge 45 of the recording paper in the transport path 23. Is done. Details of such control will be described later, but the paper feed roller 25 is rotated at the speed V1, V3, or V4 when the leading edge 45 of the recording paper is in the first section L1, and the leading edge 45 of the recording paper is the first. When it is in the second section L2, it is rotated at speed V2 or V5, and when the leading edge 45 of the recording paper is in the third section L3, it is rotated at speed V2 or V6.

  When the sheet feeding roller 25 rotates, the uppermost recording sheet is fed toward the inclined plate 22 by the frictional force between the roller surface of the sheet feeding roller 25 and the uppermost recording sheet on the sheet feeding tray 20. The leading end 45 of the recording sheet comes into contact with the inclined plate 22 and is guided upward, that is, toward the conveyance path 23. Thus, the recording paper is supplied from the paper feed tray 20 to the transport path 23 by the rotational force of the paper feed roller 25. When the uppermost recording paper is supplied from the paper feed tray 20 to the conveyance path 23, the recording paper immediately below the recording paper may be sent out together with the uppermost recording paper due to the action of friction or static electricity. However, when the leading ends 45 of the plurality of recording papers that have been multi-fed come into contact with the inclined plate 22, the recording paper is separated by the separation piece 35 in combination with the conveyance force that is going to advance in the conveyance direction. As described above, the separation piece 35 cooperates with the paper feeding roller 25 to separate the recording papers stacked on the paper feeding tray 20 and guides only the uppermost recording paper to the conveyance path 23.

  As shown in FIG. 2, a platen 42 is provided between the conveyance roller pair 59 and the discharge roller pair 64. The platen 42 is provided on the lower side of the transport path 23 and supports the recording paper transported along the transport path 23 from below. The recording unit 24 is provided above the platen 42. The recording unit 24 is disposed to face the platen 42 with a predetermined interval. The recording unit 24 includes an inkjet recording type recording head 39 and a carriage 38 on which the recording head 39 is mounted. The carriage 38 is configured to be able to reciprocate in the width direction 122 (direction perpendicular to the paper surface of FIG. 2) of the multifunction machine 10. The nozzles of the recording head 39 are exposed downward from the bottom surface of the carriage 38.

  Ink is supplied to the recording head 39 from an ink cartridge (not shown) arranged inside the printer unit 11. While the carriage 38 is moved, minute ink droplets are selectively ejected from the nozzles of the recording head 39 toward the platen 42. As a result, an image is recorded on the recording paper conveyed on the platen 42.

  The conveyance roller pair 59 is provided on the upstream side in the conveyance direction of the recording paper (hereinafter also simply referred to as “conveyance direction”) with respect to the recording unit 24 in the conveyance path 23. The conveyance roller pair 59 includes a conveyance roller 60 and a pinch roller 61. The transport roller 60 is rotatably disposed above the transport path 23. The conveyance roller 60 rotates in response to the driving force of an LF (Line Feed) motor 85 (see FIG. 3). The pinch roller 61 is rotatably disposed below the transport roller 60 and is urged toward the transport roller 60 by a spring.

  The discharge roller pair 64 is provided downstream of the recording unit 24 in the transport direction. The discharge roller pair 64 includes a discharge roller 62 and a spur 63. The paper discharge roller 62 is rotatably disposed below the conveyance path 23. The paper discharge roller 62 rotates upon receiving the driving force of the LF motor 85. The spur 63 is rotatably disposed above the paper discharge roller 62 and is urged toward the paper discharge roller 62 by a spring.

  The transport roller 60 and the paper discharge roller 62 are synchronously rotated by the driving force transmitted from the LF motor 85. For this reason, the paper discharge roller 62 and the spur 63 rotate simultaneously with the transport roller 60 and the pinch roller 61. The recording paper supplied to the transport path 23 is fed between the transport roller 60 and the pinch roller 61 in response to the rotational force of the paper feed roller 25. The recording sheet is fed onto the platen 42 under the rotational force of the conveying roller 60 while being sandwiched between the conveying roller 60 and the pinch roller 61. When the recording sheet passes over the platen 42, an image is recorded by the recording unit 24. When the leading edge 45 of the recording paper reaches between the paper discharge roller 62 and the spur 63, the recording paper is discharged by receiving the rotational force of the paper discharge roller 62 while being sandwiched between the paper discharge roller 62 and the spur 63. It is sent out above the paper tray 21.

  The registration sensor 71 is provided at a position P1 set on the upstream side in the transport direction with respect to the transport roller pair 59. The registration sensor 71 is for detecting the presence of a recording sheet at the position P1. Specifically, this is for detecting the leading edge 45 of the recording paper supplied from the paper feed tray 20 to the conveyance path 23 at the position P1. In the present embodiment, the registration sensor 71 is configured as a so-called mechanical sensor. Specifically, the registration sensor 71 includes a photo interrupter and a feeler (detector) that is pivotally supported. The photo interrupter includes a light emitting unit that emits light toward the light receiving unit, and a light receiving unit that receives the light emitted from the light emitting unit. When the light is received by the light receiving unit, a sensor signal (for example, an electrical signal corresponding to the luminance) having a level corresponding to the luminance of the received light is generated. When the recording paper supplied from the paper feed tray 20 to the conveyance path 23 reaches the position P1, the recording paper comes into contact with the feeler and the feeler is rotated. As a result, the level of the sensor signal generated by the registration sensor 71 changes. The sensor signal generated by the registration sensor 71 is output to the control unit 100 (see FIG. 3). The controller 100 detects the presence of the recording paper at the position P1 based on the change in the signal level of the sensor signal.

[Control unit 100]
The control unit 100 controls the overall operation of the multifunction machine 10 in an integrated manner. As illustrated in FIG. 3, the control unit 100 is configured as a microcomputer mainly including a CPU 101, a ROM 102, a RAM 103, an EEPROM 104, and an ASIC (Application Specific Integrated Circuit) 109. The control unit 100 controls the ASF motor 84, the LF motor 85, the printer unit 11, the driving devices of the scanner unit 12, and the like. In the present embodiment, the control unit 100 specifically implements the control means, determination means, recognition means, and timing means of the present invention.

  The ROM 102 stores a program for the CPU 101 to control the multifunction machine 10, a soft counter for counting time (timing), and the like. Further, a driver program for rotating the ASF motor 84 is also stored in the ROM 102. When the CPU 101 of the control unit 100 reads out and executes the driver program from the ROM 102, drive control of the ASF motor 84 and rotation control of the paper feed roller 25 are performed according to a procedure according to a flowchart described later.

  The ROM 102 stores various information used when the above program is executed. In the present embodiment, speed information (speeds V1 to V6) and threshold information (threshold T, first set amount, second set amount, etc.) necessary for executing the driver program are stored in the ROM 102. As the speed information, the speed V1, the speed V3, and the speed V4 are stored in the ROM 102 as the rotation speed of the paper feed roller 25 while the leading edge 45 of the recording paper is positioned in the first section L1. The speed V1 corresponds to the first speed of the present invention. The speed V3 corresponds to the second speed of the present invention. Further, the speed V2 and the speed V5 are stored in the ROM 102 as the rotation speed of the paper feed roller 25 while the leading edge 45 of the recording paper is positioned in the second section L2.

  The ROM 102 stores a set time X that is set in advance to a predetermined time. The set time X is a time for accelerating the rotational speed of the stationary paper feed roller 25 to a predetermined target speed, and is used for rotation control of the paper feed roller 25 described later.

  The RAM 103 is used as a storage area for temporarily storing various data used when the CPU 101 executes the program, or as a work area for data processing. It is also used as an area for recording a set value that is referred to when the program is executed. It is also used as an area for storing the count value C counted by the soft counter. The EEPROM 104 stores settings, flags, and the like that should be retained even after the power is turned off.

  A drive circuit 80, a rotary encoder 83, a registration sensor 71, and a drive circuit 81 are connected to the ASIC 109. In the present embodiment, the control means of the present invention is specifically realized by the drive circuit 80 and the control unit 100. Although omitted in FIG. 3, the ASIC 109 is also connected to a head control circuit for controlling the recording head 39, the operation panel 14, the scanner unit 12, and the like.

  The drive circuit 80 drives the ASF motor 84. The drive circuit 80 is connected to the ASIC 109 and the ASF motor 84. The ASIC 109 generates a PWM (Pulse Width Modulation) signal as a drive signal for energizing the ASF motor 84 in accordance with a command from the CPU 101 and outputs it to the drive circuit 80. The drive circuit 80 outputs a current corresponding to the duty ratio of the drive signal input from the ASIC 109 to the ASF motor 84. The duty ratio refers to the ratio of the ON time to the cycle time in the drive signal (PWM signal). As described above, the drive signal is supplied to the ASF motor 84 via the drive circuit 80, whereby the drive of the ASF motor 84 by the control unit 100 is controlled.

  The rotary encoder 83 detects the amount of rotation of the ASF motor 84. The rotary encoder 83 includes a rotating disk and an optical sensor (not shown). The rotating disk has a disk shape in which radial marks are written at a predetermined pitch in the circumferential direction. The rotating disk is fixed to the rotating shaft of the ASF motor 84 and rotates integrally with the rotating shaft of the ASF motor 84. In the optical sensor, a light emitting element and a light receiving element are arranged to face each other at a predetermined interval. This optical sensor is arranged so that the periphery of the rotating disk is positioned in the space between the light emitting element and the light receiving element.

  The rotary encoder 83 detects the amount of rotation of the rotating disk by counting the marks on the rotating disk based on the detection result of the optical sensor. Each time a mark on the rotating disk is detected by the optical sensor, a pulse signal is output from the optical sensor. The rotary encoder 83 detects the amount of rotation of the ASF motor 84 by counting the pulse signals output from the optical sensor. The rotation amount of the ASF motor 84 detected by the rotary encoder 83 is output to the control unit 100. The control unit 100 can determine the conveyance amount of the recording paper based on the rotation amount detected by the rotary encoder 83. Further, the control unit 100 can obtain the rotation speed of the ASF motor 84 based on the rotation amount output from the rotary encoder 83 per unit time. The controller 100 controls the rotational speed of the ASF motor 84, that is, the rotational speed of the paper feed roller 25 by changing the drive signal applied to the drive circuit 80 in accordance with the rotational speed thus obtained.

  Based on the sensor signal output from the registration sensor 71, the control unit 100 detects the presence (presence) of the recording paper at the position P1 (see FIG. 2). In other words, the control unit 100 determines based on the sensor signal output from the registration sensor 71 whether or not the leading edge 45 of the recording paper supplied from the paper feed tray 20 has reached the position P1. In the present embodiment, the detection unit of the present invention is specifically realized by the registration sensor 71 and the control unit 100.

  The drive circuit 81 drives the LF motor 85. The ASIC 109 generates a PWM signal as a drive signal for energizing the LF motor 85 in accordance with a command from the CPU 101 and outputs the PWM signal to the drive circuit 81. The drive circuit 81 outputs a current corresponding to the duty ratio of the drive signal input from the ASIC 109 to the LF motor 85. As described above, when the drive signal is energized to the LF motor 85 via the drive circuit 81, the drive of the LF motor 85 is controlled. The shaft of the transport roller 60 (see FIG. 2) and the shaft of the paper discharge roller 62 (see FIG. 2) are connected to the LF motor 85 via a drive transmission mechanism (not shown). The driving force of the LF motor 85 is transmitted to both the shaft of the transport roller 60 and the shaft of the paper discharge roller 62 via a drive transmission mechanism. As a result, the transport roller 60 and the paper discharge roller 62 rotate in synchronization.

  The printer unit 11 is provided with a rotary encoder (not shown) for detecting the rotation amount of the transport roller 60. Similar to the rotary encoder 83, the rotary encoder includes a rotating disk and an optical sensor. The rotating disk is fixed to the shaft of the transport roller 60 and rotates integrally with the transport roller 60. The optical sensor is arranged so that the periphery of the rotating disk is sandwiched between a light emitting element and a light receiving element that are arranged to face each other at a predetermined interval. The control unit 100 controls driving of the LF motor 85 based on the detection result of the rotary encoder.

[Rotation control of paper feed roller 25]
Hereinafter, an example of the processing procedure of the rotation control of the paper feed roller 25 performed by the control unit 100 when feeding the recording paper in the printer unit 11 will be described with reference to the flowcharts of FIGS. Each process described based on the flowcharts of FIGS. 4 to 6 is executed by the control unit 100 in accordance with a program stored in the ROM 102. The rotation control starts from step S1.

  First, in step S, the control unit 100 determines whether or not a recording start command has been input. Specifically, the control unit 100 determines whether or not a command for instructing recording start and recording data are received from an external device. When an operation input for instructing the start of recording is performed from the operation panel 14, it is determined whether a recording start command is input based on the presence / absence of an instruction signal generated at the time of the operation input. Here, when the control unit 100 determines that a recording start command has not been input (S1: NO), a standby state is entered. On the other hand, when it is determined that the recording start command has been input (S1: YES), the control unit 100 resets the count value C stored in the RAM 103 (S2). Specifically, the control unit 100 erases the storage area secured in the RAM 103 as an area for storing the count value C.

  Next, the control unit 100 activates the soft counter in the ROM 102 and starts counting time (S3). The process of step S3 is performed in order to count the elapsed time from when the paper feed roller 25 starts to rotate. The process of step S3 is performed almost simultaneously with the start of the paper feed roller 25. That is, the control unit 100 can count the elapsed time since the paper feed roller 25 starts to rotate by executing the process of step S3.

  The control unit 100 drives the ASF motor 84 so as to rotate the stationary paper feed roller 25 at the speed V1 almost simultaneously with the process of step S3 (S4). Specifically, the control unit 100 reads the speed V1 and the set time X from the ROM 102. The read speed V1 and set time X are stored in a set value storage area in the RAM 103. When the driver program is started by the CPU 101, the ASF motor 84 is driven and controlled based on the setting information (speed V1 and setting time X) in the setting value storage area. In step S4, the control unit 100 increases the rotational speed of the stopped ASF motor 84, and the rotational speed of the paper feed roller 25 becomes the speed V1 when the set time X has elapsed from the start of driving of the ASF motor 84. As described above, the drive signal applied to the drive circuit 80 is controlled based on the detection result of the rotary encoder 83. By controlling the driving of the ASF motor 84 in this way, as shown in FIG. 7, the stationary feed roller 25 is accelerated at an acceleration α1 (= V1 / X), and after a set time X, The rotation speed of the paper roller 25 reaches the speed V1, and then rotates at a constant speed at the speed V1. The acceleration α1 corresponds to the first acceleration of the present invention. Thus, the control for accelerating the paper feed roller 25 at the acceleration α1 corresponds to the control in the first control mode of the present invention.

  In the present embodiment, the speed V1 is set to 2 [IPS (inch per second)].

  Following the processing of step S4, the control unit 100 determines whether or not the rotation amount of the ASF motor 84 has become equal to or greater than the first set amount (S5). Specifically, the control unit 100 determines whether or not the total rotation amount of the ASF motor 84 detected by the rotary encoder 83 after the ASF motor 84 starts to rotate is equal to or greater than the first set amount. In the present embodiment, the first set amount is at least the leading edge of the recording sheet when the ASF motor 84 rotates by the first set amount without causing the sheet feeding roller 25 to fail on the recording sheet on the sheet feeding tray 20. 45 is set so as to pass through the position P0 and enter the second section L2 from the first section L1. That is, it is possible to determine whether or not the leading edge 45 of the recording sheet has entered the second section L2 from the first section L1 by the determination process in step S5. When the control unit 100 determines that the rotation amount of the ASF motor 84 is less than the first set amount (S5: NO), the process returns to step S5. In the present embodiment, when the paper feeding roller 25 slips with respect to the recording paper on the paper feeding tray 20, it is determined that the feeding of the recording paper has failed. Therefore, the first set amount is at least the leading edge 45 of the recording sheet when the ASF motor 84 rotates by the first set amount without the sheet feeding roller 25 slipping with respect to the recording sheet on the sheet feeding tray 20. Is set so that it passes through the position P0 and enters the second section L2 from the first section L1.

  When the control unit 100 determines that the rotation amount of the ASF motor 84 has become equal to or greater than the first set amount (S5: YES), the ASF motor 84 is configured to rotate the sheet feeding roller 25 rotating at the speed V1 at the speed V2. Is controlled (S6). Specifically, the control unit 100 reads the speed V2 from the ROM 102. The read speed V2 and set time X are stored in a set value storage area in the RAM 103. In other words, the speed information stored in the set value storage area is changed to the speed V2. Then, the control unit 100 drives and controls the ASF motor 84 based on the setting information (speed V2 and setting time X) in the set value recording area according to the driver program. In step S6, the control unit 100 controls the drive signal applied to the drive circuit 80 based on the detection result of the rotary encoder 83 so that the rotation speed of the paper feed roller 25 rotating at the speed V1 becomes the speed V2. To do. By performing the process of step S6, as shown in FIG. 7, in the second section L2, the paper feed roller 25 is rotated at the speed V2. That is, the rotation speed of the paper feed roller 25 that has been rotating at the speed V1 (2 [IPS]) in the first section L1 is changed to the speed V2 in the second section L2.

  In the present embodiment, the speed V2 is set to a speed larger than the speed V1. Specifically, the speed V2 is set to 6 [IPS]. As described above, when the leading edge 45 of the uppermost recording sheet in the paper feed tray 20 passes through the inclined plate 22, the frictional force that the uppermost recording sheet receives from the recording sheet immediately below the uppermost recording sheet decreases. That is, when the recording paper passes through the inclined plate 22, the paper feed roller 25 does not slip with respect to the recording paper at the uppermost position, and a recording paper feeding error hardly occurs. Therefore, in this embodiment, after the leading edge 45 of the recording paper passes through the position P0 and enters the second section L2, the rotation speed of the paper feeding roller 25 is increased in order to shorten the recording paper conveyance time. Yes. As described above, the feed roller 25 is rotated at the speed V1 until the leading edge 45 of the recording sheet enters the second section L2 from the first section L1, and the leading end 45 of the recording sheet is moved from the first section L1 to the second section L2. The control (S4 to S6) in which the speed information stored in the set value storage area is changed to the speed V2 and the paper feed roller 25 is rotated at the speed V2 (S4 to S6) is the control in the fourth control mode of the present invention. Equivalent to. The speed V1 at this time corresponds to the first target speed of the present invention, and the speed V2 corresponds to the second target speed of the present invention.

  Following the process of step S6, the control unit 100 determines whether or not the count value C is equal to or greater than the threshold value T (S7). Specifically, the control unit 100 reads out the threshold value T stored in the ROM 102 and compares the count value C with the threshold value T to determine whether or not the count value C is equal to or greater than the threshold value T. When the control unit 100 determines that the count value C is equal to or greater than the threshold value T (S7: YES), the process proceeds to step S21 described later.

  When the control unit 100 determines that the count value C is less than the threshold value T (S7: NO), the control unit 100 determines whether there is a recording sheet at the position P1 based on the sensor signal output from the registration sensor 71. (S8). When the recording sheet has not yet reached the position P1 and the control unit 100 determines that there is no recording sheet at the position P1 (S8: NO), the process returns to step S7. Here, the threshold value T is set such that when the uppermost recording sheet is normally supplied to the uppermost recording sheet in the sheet feeding tray 20 without slipping, the feeding roller 25 rotates. It is set slightly longer than the time A from the beginning until the leading edge 45 of the recording paper is detected by the registration sensor 71. Therefore, the control unit 100 determines that the paper feed roller 25 has slipped with respect to the recording paper on the paper feed tray 20 when it is determined “NO” in step S8 and “YES” in step S7. can do. In other words, the control unit 100 feeds the recording paper on the paper feeding tray 20 on the condition that the count value C is equal to or greater than the threshold T in the state where no recording paper exists at the position P1. It can be determined that the roller 25 has slipped. By setting the threshold value T in this way, it is possible to easily and reliably determine whether the paper feed roller 25 has slipped with respect to the uppermost recording paper. The time A is obtained based on, for example, the length of the recording paper transport path from the inclined plate 22 to the position P1 in the transport path 23, the outer diameter of the paper feed roller 25, the rotational speed of the paper feed roller 25, and the like. It is done.

  When the count value C is less than the threshold value T (S7: NO) and the control unit 100 determines that there is a recording sheet at the position P1 (S8: YES), the leading end 45 of the recording sheet is in the second section L2. It can be determined that the vehicle has entered the third section L3. In this case, the control unit 100 determines whether the recording sheet is the first sheet or the second sheet (S9). The determination to be made is made based on the type information that is previously input from the external information device or the operation panel 14 and stored in the RAM 103. When the control unit 100 determines that the recording paper is the first sheet (plain paper in the present embodiment) (S9: first sheet), the processing is performed while the rotation speed of the paper feed roller 25 is maintained at the speed V2. The process proceeds to step S11. That is, in the third section L3, the paper feed roller 25 continues to rotate at the speed V2 (6 [IPS]) (see FIG. 7).

  When the control unit 100 determines that the recording paper is the second sheet (inkjet paper or glossy paper in the present embodiment) (S9: second sheet), the control unit 100 reduces the rotation speed of the paper feed roller 25 (S10). Specifically, the control unit 100 changes the speed information (speed V2) stored in the set value storage area in the RAM 103 to a speed 1 [IPS] smaller than the speed V2. And the control part 100 changes the rotational speed of the ASF motor 84 by controlling the drive signal given to the drive circuit 80 based on the setting information of the set value storage area. As a result, the rotation speed of the paper feed roller 25 is changed to a speed 1 [IPS] smaller than the speed V2. In the present embodiment, as indicated by a broken line in FIG. 7, in the third section L3, the rotation speed of the paper feed roller 25 is changed from the speed V2 (6 [IPS]) to 5 [IPS].

  When the recording paper is ink-jet paper or glossy paper that is less likely to bend than plain paper, if the rotation speed of the paper feed roller 25 is too high while the leading edge 45 of the recording paper is positioned in the third section L3, the recording paper However, there is a risk that the recording sheet will be caught between the stationary conveying roller pair 59 due to excessively entering the pressure contact portion of the conveying roller pair 59. Temporarily, in the printer unit 11, the leading end of the recording paper that has reached the conveying roller pair 59 is brought into contact with the stationary conveying roller pair 59 to adjust the leading end of the recording paper to correct skew (so-called “registration processing”). When the recording paper is sandwiched between the conveying roller pair 59 as described above, the leading edge of the recording paper cannot be adjusted. When the recording paper is conveyed by the conveyance roller pair 59 in this state, image recording is performed on the oblique recording paper. In the present embodiment, as described above, such a problem is prevented by reducing the rotation speed of the paper feed roller 25 when the recording paper is the second sheet.

  The control unit 100 determines that the amount of rotation of the ASF motor 84 after the leading edge 45 of the recording paper passes the position P1 after determining that it is “first sheet” in step S9 or performing the process of step S10. It is determined whether or not the amount exceeds two set amounts (S11). Here, the second set amount corresponds to the distance that the paper feed roller 25 conveys the recording sheet when the ASF motor 84 is rotated by the second set amount. The value is set to be slightly larger than the distance to the pressure contact position with the roller 61. For this reason, the control unit 100 can determine whether or not the leading edge 45 of the recording sheet has reached the pressure contact position between the conveying roller 60 and the pinch roller 61 by the determination processing in step S11. When the control unit 100 determines that the rotation amount of the ASF motor 84 is less than the second set amount (S11: NO), the process is returned to step S11.

  When the control unit 100 determines that the rotation amount of the ASF motor 84 is equal to or greater than the second set amount (S11: YES), the control unit 100 controls the drive signal to be applied to the drive circuit 80 as shown in FIG. The motor 84 is stopped (S15). Subsequently, the control unit 100 performs a transport operation (S16). Specifically, the control unit 100 controls the drive signal applied to the drive circuit 81 to drive the LF motor 85. As a result, the driving force of the LF motor 85 is transmitted to the transport roller 60 and the paper discharge roller 62, and the recording paper is transported toward the paper discharge tray 21. When the recording sheet passes over the platen 42, an image is recorded by the recording unit 24.

  The control unit 100 determines whether or not the recording paper is discharged to the paper discharge tray 21 under the rotational force of the transport roller 60 or the paper discharge roller 62 (S17). Specifically, the control unit 100 determines whether the total rotation amount of the transport roller 60 after the processing of Step S16 has reached a predetermined amount or more based on a detection result of a rotary encoder (not shown). . When the control unit 100 determines that the recording paper is not discharged to the paper discharge tray 21, that is, the total rotation amount of the transport roller 60 is less than a predetermined amount (S17: NO), the process returns to step S17.

  When the control unit 100 determines that the recording sheet has been discharged to the discharge tray 21, that is, determines that the total rotation amount of the transport roller 60 has reached a predetermined amount or more (S17: YES), the recording data of the next page is stored. It is determined whether or not there is (S18). That is, the control unit 100 determines whether or not the recording data for the next page is stored in the RAM 103. If the control unit 100 determines that there is recording data for the next page (S18: YES), the process returns to step S2. When the control unit 100 determines that there is no recording data for the next page (S18: NO), a series of processing is completed.

  4, when the control unit 100 determines that the count value C is equal to or greater than the threshold value T (S7: YES), that is, when it is determined that the paper feed roller 25 has slipped, the control unit 100 is illustrated in FIG. Thus, the ASF motor 84 is stopped (S21). The process of step S <b> 21 is performed by controlling the drive signal that the control unit 100 gives to the drive circuit 80.

  Next, the control unit 100 resets the count value C (S22). Specifically, the control unit 100 erases the storage area secured in the RAM 103 as an area for storing the count value C. Then, the control unit 100 determines whether the recording sheet is the first sheet or the second sheet (S23). The process of step S23 is performed in the same manner as the process of step S9.

  When determining that the recording sheet is the first sheet (S23: first sheet), the control unit 100 drives the ASF motor 84 to rotate the stationary sheet feeding roller 25 at the speed V3 (S24). Specifically, the control unit 100 reads the speed V3 and the set time X from the ROM 102. The read speed V3 and set time X are stored in a set value storage area in the RAM 103. In other words, the speed information stored in the set value storage area is changed to the speed V3. Then, the control unit 100 drives and controls the ASF motor 84 based on the setting information (speed V3 and setting time X) in the set value recording area according to the driver program. In step S24, the control unit 100 increases the rotational speed of the stopped ASF motor 84, and the rotational speed of the paper feed roller 25 becomes the speed V3 when the set time X has elapsed from the start of driving of the ASF motor 84. As described above, the drive signal applied to the drive circuit 80 is controlled based on the detection result of the rotary encoder 83. By controlling the driving of the ASF motor 84 in this way, as shown in FIG. 8, the sheet feeding roller 25 in a stationary state is accelerated at an acceleration α2 (= V3 / X). The rotation speed of the paper roller 25 reaches the speed V3, and then rotates at a constant speed at the speed V3. The acceleration α2 corresponds to the second acceleration of the present invention. Thus, the control for accelerating the paper feed roller 25 at the acceleration α2 corresponds to the control in the second control mode of the present invention.

  In the present embodiment, the speed V3 is set to a speed larger than the speed V1. Specifically, the speed V3 is set to 5 [IPS].

  As described above, the control unit 100 determines that the rotation speed of the paper feed roller 25 is changed from the first speed on the condition that it is determined that the paper feed roller 25 has slipped and the sheet to be conveyed is the first sheet. Change the setting to the second speed. As a result, the acceleration at the start of the paper feed roller 25 is changed from the acceleration α1 to the acceleration α2.

  When determining that the recording sheet is the second sheet (S23: second sheet), the control unit 100 drives the ASF motor 84 to rotate the stationary sheet feeding roller 25 at the speed V4 (S25). Specifically, the control unit 100 reads the speed V4 and the set time X from the ROM 102. The read speed V4 and set time X are stored in a set value storage area in the RAM 103. In other words, the speed information stored in the set value storage area is changed to the speed V4. Then, the control unit 100 drives and controls the ASF motor 84 based on the setting information (speed V4 and setting time X) in the set value recording area according to the driver program. In step S25, the control unit 100 increases the rotational speed of the stopped ASF motor 84, and when the set time X has elapsed from the start of driving of the ASF motor 84, the rotational speed of the paper feed roller 25 becomes the speed V4. As described above, the drive signal applied to the drive circuit 80 is controlled based on the detection result of the rotary encoder 83. By controlling the driving of the ASF motor 84 in this manner, as shown in FIG. 8, the stationary feed roller 25 is accelerated at the acceleration α3 (= V4 / X), and after the set time X, the feeding is performed. The rotation speed of the paper roller 25 reaches the speed V4, and then rotates at a constant speed at the speed V4. The acceleration α3 corresponds to the third acceleration of the present invention. Thus, the control for accelerating the paper feed roller 25 at the acceleration α3 corresponds to the control in the third control mode of the present invention.

  In the present embodiment, the speed V4 is set to be higher than the speed V1 and the speed V3. Specifically, the speed V4 is set to 6 [IPS].

  Here, when the recording paper placed on the paper feed tray 20 is the first sheet (plain paper in the present embodiment), if the acceleration at the time of activation of the paper feed roller 25 is too high, There is a possibility that the uppermost recording sheet is damaged by receiving the rotational force of the paper feed roller 25. Conversely, when the recording paper placed on the paper feed tray 20 is a second sheet (inkjet paper or glossy paper in this embodiment), the second sheet is the first when the paper is supplied to the conveyance path 23. Receives greater transport resistance than the sheet. For this reason, if the acceleration at the time of starting of the paper feed roller 25 is too low, the second sheet may not be normally supplied to the conveyance path 23. Therefore, as described in steps S23 to S25, the acceleration α3 of the paper feed roller 25 when the recording paper is the second sheet is the acceleration α2 of the paper feed roller 25 when the recording paper is the first sheet. The driving of the ASF motor 84 is controlled so as to be larger than that.

  The control unit 100 starts counting the count value C almost at the same time when the ASF motor 84 is activated by the process of step S24 or step S25 (S26). Then, the control unit 100 determines whether or not the rotation amount of the ASF motor 84 is equal to or greater than the first set amount (S27). When the control unit 100 determines that the rotation amount of the ASF motor 84 is less than the first set amount (S27: NO), the process is returned to step S27. When the control unit 100 determines that the rotation amount of the ASF motor 84 is equal to or greater than the first set amount (S27: YES), the control unit 100 drives the ASF motor 84 so that the rotation speed of the paper feed roller 25 becomes the speed V5. (S28). Specifically, the control unit 100 reads the speed V5 and the set time X from the ROM 102. Then, the speed information stored in the set value storage area is changed to the speed V5. Thereafter, the control unit 100 drives and controls the ASF motor 84 based on the setting information (speed V5 and setting time X) in the set value recording area according to the driver program. In step S28, the control unit 100 controls the drive signal applied to the drive circuit 80 based on the detection result of the rotary encoder 83 so that the rotation speed of the paper feed roller 25 becomes the speed V5. By controlling the driving of the ASF motor 84 in this way, the paper feed roller 25 rotates at a speed V5 as shown in FIG.

  In the present embodiment, the speed V5 is set to the same speed as the speed V3, that is, 5 [IPS].

[Operational effects of this embodiment]
As described above, when the control unit 100 determines that the paper feeding roller 25 slips with respect to the uppermost recording paper on the paper feeding tray 20, the paper feeding roller 25 is temporarily stopped, and then the recording paper is loaded. When the paper feed roller 25 is rotated again for refeeding, the paper feed roller 25 is accelerated at an acceleration α2 or an acceleration α3 that is greater than the acceleration α1. By changing the acceleration of the paper feed roller 25 from the acceleration α1 to the acceleration α2 or the acceleration α3, the static frictional force between the paper feed roller 25 and the uppermost recording paper is increased. As a result, when the paper feeding roller 25 slipped with respect to the uppermost recording paper is rotated again for refeeding, the feeding of the paper feeding roller 25 to the recording paper is improved, and the paper feeding to the recording paper is performed. The slip of the roller 25 is prevented. Note that the cause of slipping of the paper feed roller 25 is, for example, wear of the roller surface of the paper feed roller 25 or reduction in frictional force due to paper dust or the like. Therefore, when the paper feed roller 25 slips, the recording paper conveying force by the paper feed roller 25 is significantly reduced. For this reason, even if the acceleration of the paper feed roller 25 is changed from the acceleration α1 to the acceleration α2 or the acceleration α3, the paper feed roller 25 does not bite excessively on the recording paper on the paper feed tray 25. Therefore, even if the acceleration is changed, the recording paper is not easily fed to the transport path 23 more than when the paper feed roller 25 is in a normal state.

  Further, in this embodiment, when the control unit 100 determines that the paper feed roller 25 has slipped, the set time X remains unchanged, and the speed V3 or the speed V4 where the rotational speed of the paper feed roller 25 is greater than the speed V1. Changed to For this reason, for example, compared with the case where the set time X for accelerating the paper feed roller 25 is shortened and the acceleration at the time of starting the paper feed roller 25 is increased, the paper feed roller 25 is positioned at the uppermost position on the paper feed tray 20 A longer time is secured to bite the recording paper. Therefore, the slip of the paper feed roller 25 is effectively prevented.

[Modification]
Note that, as shown in FIG. 9, regardless of whether or not the paper feed roller 25 slips with respect to the recording paper on the paper feeding tray 20, the leading edge of the recording paper is located in the first section L1. It is conceivable that the set value of the rotation speed of the paper feeding roller 25 is a constant value (in this embodiment, the speed V1 (= 2 [IPS])). In this case, the set time X1 (corresponding to the first set time in the present invention) and the set time X2 (in the present invention) are used as the time for accelerating the rotation speed of the stationary paper feed roller 25 to the target speed V1. (Corresponding to the second set time) is stored in the ROM 102 as a set value. The set time X2 is shorter than the set time X1. The set time X1 and the set time X2 are elements that can be arbitrarily set according to the requested acceleration of the paper feed roller 25.

  In this modification, the set time X1 and the set time X2 are applied to the acceleration control of the paper feed roller 25. Specifically, the following process is executed instead of the above-described process of S4 (see FIG. 4). That is, the control unit 100 reads the speed V1 and the set time X1 from the ROM 102, and stores the read speed V1 and set time X1 in the set value storage area in the RAM 103. Thereafter, when the driver program is activated by the CPU 101, the ASF motor 84 is driven and controlled based on the setting information (speed V1 and setting time X1) in the setting value storage area. Specifically, the control unit 100 increases the rotational speed of the stopped ASF motor 84 so that the rotational speed of the paper feed roller 25 becomes the speed V1 when the set time X1 has elapsed from the start of driving of the ASF motor 84. In addition, the drive signal applied to the drive circuit 80 is controlled based on the detection result of the rotary encoder 83. By controlling the driving of the ASF motor 84 in this way, the stationary paper feed roller 25 is accelerated at the acceleration α1 (= V1 / X1), and the rotational speed of the paper feed roller 25 is increased after the set time X1. V1 is reached, and then it rotates at a constant speed V1.

  Further, the following processing is executed instead of the processing of S24 (see FIG. 5) described above. That is, the control unit 100 reads the speed V3 and the set time X2 from the ROM 102, and stores the read speed V3 and the set time X2 in the set value storage area in the RAM 103. In other words, the set time information stored in the set value storage area is changed to the set time X2. Thereafter, the control unit 100 controls driving of the ASF motor 84 based on the setting information (speed V3 and setting time X2) in the set value recording area according to the driver program. Specifically, the control unit 100 increases the rotational speed of the stopped ASF motor 84 so that the rotational speed of the paper feed roller 25 becomes the speed V3 when the set time X2 has elapsed from the start of driving of the ASF motor 84. In addition, the drive signal applied to the drive circuit 80 is controlled based on the detection result of the rotary encoder 83. By controlling the driving of the ASF motor 84 in this way, the stationary paper feed roller 25 is accelerated at the acceleration α2 (= V3 / X2), and the rotational speed of the paper feed roller 25 is increased after the set time X2. V3 is reached, and then it rotates at a constant speed V3. Note that the processing similar to the processing described above is executed instead of the processing in step S25.

  In the present embodiment, the form in which the rotation speed of the paper feed roller 25 (ASF motor 84) is changed in the first section L1 to the third section L3 has been described. However, the rotation of the paper feed roller 25 (ASF motor 84) is described. The speed may be constant between the first section L1 and the third section L3.

  In the present embodiment, the form in which the acceleration at the time of starting the paper feed roller 25 is changed according to the type of the recording paper has been described. However, when it is determined that the paper feed roller 25 has slipped, the recording paper is loaded. Regardless of whether the sheet is the first sheet or the second sheet, the stationary sheet feeding roller 25 may be accelerated at the acceleration α2.

  In the present embodiment, the form in which it is determined that the paper feeding roller 25 slips has been described on the condition that the count value C is equal to or greater than the threshold value T without detecting the recording paper by the registration sensor 71. Instead, for example, when the recording sheet is not detected by the registration sensor 71 even though the rotation amount of the ASF motor 84 detected by the rotary encoder 83 reaches a predetermined rotation amount, the sheet feeding is performed. It may be determined that the roller 25 has slipped.

  In this embodiment, the case where the sheet conveying apparatus of the present invention is applied to the printer unit 11 has been described. However, the sheet conveying apparatus may be applied to the ADF 29 of the scanner unit 12. In this case, it is possible to prevent a problem that the rollers slip with respect to the documents on the document tray 30 and the rollers are not conveyed.

FIG. 1 is an external perspective view of a multifunction machine 10 according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the internal structure of the printer unit 11. FIG. 3 is a block diagram illustrating the configuration of the control unit 100. FIG. 4 is a flowchart illustrating an example of a processing procedure of rotation control performed by the control unit 100 when the recording paper is fed in the printer unit 11. FIG. 5 is a flowchart illustrating an example of a rotation control processing procedure performed by the control unit 100 when the printer unit 11 feeds a recording sheet. FIG. 6 is a flowchart illustrating an example of a rotation control processing procedure performed by the control unit 100 when the printer unit 11 feeds a recording sheet. FIG. 7 is a graph illustrating a change in the rotation speed of the paper feed roller 25. FIG. 8 is a graph illustrating a change in the rotation speed of the paper feed roller 25. FIG. 9 is a graph illustrating the change in the rotation speed when the paper feed roller 25 is accelerated in a modification of the present embodiment.

11: Printer unit (an example of an image recording apparatus of the present invention)
14 ... operation panel (a part of receiving means of the present invention)
20... Paper feed tray (an example of a placement unit of the present invention)
35 ... separation piece (an example of the separation member of the present invention)
23... Transport path (an example of the transport path of the present invention)
24... Recording section (an example of recording means of the present invention)
25: Paper feed roller (an example of the roller of the present invention)
26 ... Arm (an example of the arm of the present invention)
50: Recording paper (an example of the sheet of the present invention)
71 ... Registration sensor (part of detection means of the present invention)
80 ... Drive circuit (part of the control means of the present invention)
83... Rotary encoder (a part of the control means of the present invention)
84... ASF motor 100... Control unit (an example of determination means of the present invention, a part of the control means of the present invention, a part of the recognition means of the present invention, a part of the detection means of the present invention, the present invention An example of time measuring means)

Claims (7)

A placement unit on which at least one sheet is placed;
A roller for feeding a sheet from the placement section to the conveyance path;
Is arranged above the upper mounting section, rotatably supports the roller, around the upstream side of the feeding direction of the sheet than the roller, rotatable arm the roller toward or away from the sheet When,
Control means for accelerating the roller in a stationary state and rotating it at a preset target speed;
Determination means for determining whether or not the roller has failed to feed the sheet on the placement section during control by the control means,
The control means includes
Until the determination unit determines that the roller has failed to feed the sheet, the rotation of the roller is controlled in the first control mode in which the roller is accelerated at the first acceleration, and the roller feeds the sheet. The roller is stopped in the second control mode in which the roller is accelerated at a second acceleration higher than the first acceleration after the roller is stopped on the condition that the determination unit determines that the failure has occurred. The sheet conveying device to be controlled.   A placement unit on which at least one sheet is placed;
  An arm that is disposed above the mounting portion and is rotatable in a direction of contacting and separating from the mounting portion;
  A roller rotatably provided at the tip side of the arm, abutting in a stationary state on a sheet placed on the placement unit, and supplying a sheet from the placement unit to the conveyance path;
  Control means for accelerating the roller in a stationary state and rotating it at a preset target speed;
  Determination means for determining whether or not the roller has failed to feed the sheet on the placement section during control by the control means,
  The control means includes
  Until the determination unit determines that the roller has failed to feed the sheet, the rotation of the roller is controlled in the first control mode in which the roller is accelerated at the first acceleration, and the roller feeds the sheet. The roller is stopped in the second control mode in which the roller is accelerated at a second acceleration higher than the first acceleration after the roller is stopped on the condition that the determination unit determines that the failure has occurred. The sheet conveying device to be controlled. The control means is for accelerating the roller to the target speed after a preset time has elapsed since the start of acceleration control of the roller. The set value of the target speed is changed from the first speed to the first speed. by changing the second speed greater than the speed, the sheet conveying apparatus according to claim 1 or 2 is switched from the first control mode to the second control mode. The control means is for accelerating the roller to the target speed after a preset time has elapsed since the start of acceleration control of the roller, and the set value of the set time is changed from the first set time to the first set time. 3. The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is switched from the first control mode to the second control mode by changing to a second setting time shorter than the one setting time. Recognizing means for recognizing the type of sheet placed on the placement section,
The control means is provided on the condition that the determination means determines that the roller has failed to feed the sheet, and the recognition means recognizes that the sheet of the placement section is the first sheet having a predetermined thickness. In addition, after the roller is stopped, the rotation of the roller is controlled in the second control mode, and it is determined by the determination means that the roller has failed to feed the sheet, and the sheet of the placement unit is Third , the roller is stopped at a third acceleration greater than the second acceleration after the roller is stopped on the condition that the second sheet is thicker than the first sheet by the recognition unit. sheet conveying apparatus according to any one of the control mode from the claim 1 for controlling the rotation of the roller 4. Provided on the downstream side of the sheet in the conveying direction of the sheet placed on the placement unit, and provided with a separating member for separating the sheet stacked on the placement unit,
The control means sets the target speed to the first target speed and rotates the roller until the downstream end of the sheet on the placement section passes through the separating member, and rotates the roller on the downstream side. 2. The rotation of the roller is controlled in a fourth control mode in which the target speed is set to a second target speed larger than the first target speed after the end portion has passed through the separation member, and the roller is rotated. To 5. The sheet conveying device according to any one of 5 to 5. A sheet conveying device according to any one of claims 1 to 6;
An image recording apparatus comprising: a recording unit configured to record an image on a sheet fed to the conveyance path by the roller.

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