Paper feeding device and image forming apparatus including the same

Abstract

A paper feeding device includes a sensor, a roller and a bracket, wherein the sensor and the roller are arranged on the bracket. The bracket supports the sensor and the roller so that the sensor and the roller contact the surface of a paper roll. The sensor and the roller face the axial center of the paper roll. The roller and the sensor are arranged spaced apart in the circumferential direction of the paper roll. The sensor has a detection accuracy capable of detecting a step at the front end of the paper roll.

Description

Technical Field

[0001] Embodiments of the present invention generally relate to a paper feeding device and an image forming apparatus including the paper feeding device. Background Art

[0002] As is known, various image forming apparatuses that process a paper roll include a paper feeding mechanism that performs a paper feeding action after a user manually inserts a leading end of the paper roll into a paper feeder and the image forming apparatus detects the leading end of the paper roll.

[0003] When the known image forming apparatus performs a paper feeding operation, the user needs time to manually insert the leading end of the paper roll into the paper feeder. When feeding the paper, the leading end of the paper inserted obliquely into the paper feeder causes the direction of the paper to be tilted, thus requiring a service call.

[0004] In addition, for example, PTL (JP-2018-150107-A) discloses a technology in which an image forming apparatus includes a sensor that changes an output value according to a distance to paper. The image forming apparatus rotates a paper roll in a paper winding direction so that paper is separated from the paper roll, and the sensor then detects the leading end of the paper peeled off or separated from the paper roll. However, since the separation state of the paper changes due to the thickness, rigidity, and curling state of the paper, it is impossible to eliminate the inconvenience that the output value of the sensor becomes unstable. Summary of the invention

[0005] Technical issues

[0006] An object of the present invention is to provide a paper feeding device capable of reliably detecting the leading end of a paper roll and feeding the paper to a paper feeder, and an image forming apparatus including the paper feeding device.

[0007] Solutions to the problem

[0008] According to one aspect of the present invention, a paper feeding device includes a sensor, a roller and a bracket, wherein the sensor and the roller are arranged on the bracket. The bracket supports the sensor and the roller so that the sensor and the roller contact the surface of the paper roll. The sensor and the roller face the axial center of the paper roll. The roller and the sensor are arranged spaced apart in the circumferential direction of the paper roll. The sensor has a detection accuracy capable of detecting a step at the front end of the paper roll.

[0009] Effects of the Invention

[0010] According to the present invention, the leading end of the paper roll can be reliably detected and fed into the paper feeder. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings are intended to illustrate example embodiments of the present invention and should not be interpreted as limiting the scope thereof. Unless explicitly stated, the accompanying drawings should not be considered to be drawn to scale. Moreover, the same or similar reference numerals represent the same or similar components in several views.

[0012] Figure 1 is an exemplary diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

[0013] Figure 2 is a schematic cross-sectional view showing the configuration of an image forming apparatus according to an embodiment of the present invention.

[0014] Figure 3A , 3B , 3C, 3D, and 3E are diagrams for explaining comparative methods of setting paper rolls, respectively.

[0015] Figure 4 It means in Figure 1 A side view of a main part of an example of a structure of a paper feeding device according to an embodiment of the present invention in an image forming apparatus.

[0016] Figure 5 is a block diagram showing a functional example of a paper feeding device according to an embodiment of the present invention.

[0017] Figure 6 1 is a flowchart showing an example of an operation of setting a paper roll in a paper feeding device according to an embodiment of the present invention.

[0018] Fig. 7A , 7B 7A and 7B are diagrams showing structural examples of arms according to an embodiment of the present invention, respectively.

[0019] Fig. 8A , 8B 8C are diagrams showing examples of the operation of detecting the leading end of the paper roll.

[0020] Fig. 9A and 9B These are diagrams for explaining the difference caused by the position of the roller relative to the sensor.

[0021] Fig. 10A and 10B Each of them is a diagram showing an example of a signal waveform detected by a sensor.

[0022] Fig.11 It is a diagram for explaining a case where there are concave streaks or concave scratches on the surface of a paper roll.

[0023] Fig. 12A and 12B They are graphs showing the friction load applied to the surface of the paper roll when the actuator of the sensor contacts the surface of the paper roll.

[0024] Fig.13 FIG. 1 is an exemplary diagram for explaining that the actuator has a tip that contacts a paper roll and is equipped with a roller.

[0025] Fig.14 This is a diagram for explaining an example in which a sensor and a roller are provided near an entrance guide for paper transport. DETAILED DESCRIPTION

[0026] Now, a paper feeding device according to the present invention and an image forming apparatus according to the present invention are described with reference to the accompanying drawings. Note that the following embodiments are not limited to the present invention, and any deletion, addition, modification, change, etc. can be made within the scope that can be conceived by those skilled in the art, including other embodiments, and any of them is included in the scope of the present invention as long as the effects and features of the present invention are demonstrated. In addition, in the drawings, the same reference numerals are given to the same components and corresponding components having the same configuration or function, and their redundant descriptions will be omitted.

[0027] The paper feeding device according to the embodiment of the present invention feeds paper from a paper roll. The paper roll is a recording medium formed by winding a long paper (also referred to as "paper") in a roll shape.

[0028] Reference Figure 1 and Figure 2 A configuration example of an image forming apparatus to which a paper feeding device according to an embodiment of the present invention is applied is described.

[0029] The image forming apparatus as one aspect of an embodiment of the present invention is an inkjet printer that prints on a recording medium by ejecting ink droplets corresponding to image data, but the structure of the image forming apparatus is not limited to an inkjet printer. For example, the present invention can be applied to an image forming apparatus that uses an electrophotographic method to convey and print a recording medium, such as a copier and a printer.

[0030] Figure 1 An exemplary perspective view showing a schematic structure of an image forming apparatus 80 according to an embodiment of the present invention. Figure 2 Yes means Figure 1 A cross-sectional side view of the structure of the image forming device in FIG. Figure 1 and Figure 2 The overall structure and operation of the image forming apparatus 80 according to the embodiment of the present invention will be described. Figure 1 , arrow X indicates the depth direction (front-back direction) of the image forming apparatus 80 (hereinafter referred to as the X direction), arrow Y indicates the width direction (main scanning direction) of the image forming apparatus 80 (hereinafter referred to as the Y direction), and arrow Z indicates the vertical direction (up-down direction) of the image forming apparatus 80 (hereinafter referred to as the Z direction).

[0031] like Figure 1 As shown in FIG. 1 , the image forming apparatus 80 is a tandem type image forming apparatus of a liquid jetting method (ink jetting method), and has a housing 81 and a housing frame 82. The housing 81 is mounted on the housing frame 82. In the image forming apparatus 80, the main guide rod 64 and the auxiliary guide rod 65 are connected to each other. Figure 1 The main guide rod 64 is connected across the housing 81 in the main scanning direction corresponding to the Y direction indicated by the double-headed arrow. The main guide rod 64 movably supports the carriage 66, and the carriage 66 includes a connecting member 66a engaged with the sub-guide rod 65 to stabilize the posture of the carriage 66.

[0032] The image forming apparatus 80 includes a timing belt 67 along the main guide rod 64. The timing belt 67 is an endless belt stretched between a driving wheel 68 and a driven wheel 69. The driving wheel 68 is driven and rotated by a main scanning motor 70. The driven wheel 69 is set in a state where the driven wheel 69 applies a predetermined stretching amount to tighten the timing belt 67. When the main scanning motor 70 drives the driving wheel 68 to rotate, the driving wheel 68 rotates the timing belt 67 in the main scanning direction according to the rotation direction of the driving wheel 68.

[0033] The carriage 66 is connected to the timing belt 67. When the driving wheel 68 rotates to move the timing belt 67 in the main scanning direction, the carriage 66 reciprocates along the main guide rod 64 in the main scanning direction.

[0034] The image forming apparatus 80 further includes a cartridge holder 71 and a maintenance unit 72. The cartridge holder 71 and the maintenance unit 72 are detachably connected (stored) to one end of the housing 81 in the main scanning direction (Y direction). The cartridge holder 71 accommodates cartridges 73, which contain inks of corresponding colors such as yellow (Y), magenta (M), cyan (C) and black (K). Each cartridge 73 is replaceably stored in the cartridge holder 71. The carriage 66 has recording heads of corresponding colors such as yellow (Y), magenta (M), cyan (C) and black (K). Each cartridge 73 of the cartridge holder 71 is connected to the recording head of the corresponding color through a pipeline. With this structure, ink is supplied to the recording head of the corresponding color from the cartridge 73 of the cartridge holder 71 via the pipeline.

[0035] In the image forming apparatus 80, when the carriage 66 moves in the main scanning direction, the recording head provided in the carriage 66 ejects ink droplets of corresponding colors onto the paper P which is scanned in the sub-scanning direction ( Figure 1 The X direction indicated by the arrow in the middle) is on the pressing plate (disk) 74 (see Figure 2 ) is intermittently conveyed on the paper P. Thus, the image forming device 80 records the image on the paper P.

[0036] The paper P is not limited to paper, but may be various types of sheets, such as roll film. For the sake of convenience, the paper during paper transportation is referred to as paper P, the roll paper P is referred to as paper roll Pr (Pa, Pb), and the core tube (core portion) of the paper roll Pr is referred to as core tube Ps.

[0037] like Figure 2As shown, the image forming apparatus 80 further includes a chamber 75 provided with a fan. The chamber 75 is provided below the platen 74. When the fan of the chamber 75 is driven, the paper P is conveyed on the platen 74 while the paper P is in close contact with the platen 74.

[0038] The image forming apparatus 80 intermittently conveys the paper P in the sub-scanning direction. Then, while the conveyance of the paper P in the sub-scanning direction is stopped, as the carriage 66 moves in the main scanning direction, ink droplets are ejected from the nozzle arrays of the corresponding recording heads provided on the carriage 66 onto the paper P on the platen 74. Thus, a roll-shaped image is formed (recorded) on the paper P.

[0039] The maintenance unit 72 performs maintenance of the recording head, such as cleaning the ink outlet surface of the recording head, capping the recording head, and discharging (removing) unused ink. By doing so, the maintenance unit 72 discharges (removes) unnecessary ink from the recording head and maintains the reliability of the recording head.

[0040] The image forming apparatus 80 further includes an encoder sheet parallel to the timing belt 67 and the main guide rod 64 at least within the moving range of the carriage 66. The carriage 66 has an encoder sensor for reading the encoder sheet. The image forming apparatus 80 controls the driving of the main scanning motor 70 according to the sensing result obtained by reading the encoder sheet by the encoder sensor, thereby controlling the movement of the carriage 66 in the main scanning direction.

[0041] In addition, a reflective sensor (e.g., an encoder sensor and a paper leading end detection sensor) mounted on the carriage 66 detects both lateral ends of the paper P conveyed to the image forming device 60. At this time, the size of the paper P is detected based on the position of the lateral end of the paper P in the main scanning direction read by the paper leading end detection sensor.

[0042] like Figure 1 and Figure 2 As shown, the image forming device 80 further includes two roll bearing seats 5a and 5b located on a housing frame 82 of a supporting housing 81 of the image forming device 80. The roll bearing seats 5a and 5b are arranged vertically, that is, Figure 1 and Figure 2 In the vertical direction (Z direction).

[0043] like Figure 1 and Figure 2 As shown in FIG. 1 , the paper roll Pr is arranged on the reel bearing seats 5a and 5b. More specifically, as shown in FIG. Figure 1As shown in FIG. 1 , the paper roll Pa is arranged on the roll bearing seat 5a, and the paper roll Pb is arranged on the roll bearing seat 5b. When the paper P (in a roll shape) is pulled out from the front end of the paper roll Pa arranged on the roll bearing seat 5a or the front end of the paper roll Pb arranged on the roll bearing seat 5b, the paper P is conveyed in the corresponding paper conveying passage 9 by the paired paper conveying rollers 6a and 6b, the positioning roller 10 and the positioning pressure roller 17, as shown in FIG. Figure 2 Indicated by the arrow.

[0044] The controller 100 controls the driving devices 7 a and 7 b to rotate the pair of paper conveying rollers 6 a and 6 b , the registration roller 10 , and the registration pressure roller 17 .

[0045] The paper roll receiving seats 8a and 8b are provided below the paper rolls Pr (ie, the paper rolls Pa and Pb) to prevent the paper rolls Pr from falling off the reel bearing seats 5a and 5b.

[0046] The paper P is supported by the corresponding medium conveying guides 18a and 18b and partially defined to pass through the corresponding one of the paper conveying paths 9. Then, the paper P is conveyed to the platen 74 in the image forming device 60. Note that in the case of performing double-sided printing to form images on both sides (both sides) of the paper P, the paper P is reversed in the paper reversing unit 19 so that the front side of the paper P is reversed to the back side.

[0047] In the image forming device 60, a recording head containing ink of each color ejects ink droplets (liquid) of each color onto the paper P according to image data, and thus the image forming device 60 forms an image on the paper P. The paper conveying direction ( Figure 1 A cutter 76 is provided at the paper discharge section in the normal direction T (positive X direction in FIG. 1 ). The cutter 76 extends in the sub-scanning direction (ie, the paper width direction and the Y direction) and cuts the continuous paper P into predetermined lengths.

[0048] In order to align the front end of the continuous paper P supplied from the paper roll Pr, the cutter 76 is fixed to a wire or a timing belt wound or stretched between a plurality of wheels. One of the plurality of wheels is connected to a driving motor. When the driving motor drives and conveys the continuous paper P in the main scanning direction (i.e., the Y direction), the paper P is cut into a predetermined length. The cut paper P is discharged to the paper discharge portion.

[0049] Please note that Figure 1 and Figure 2 The image forming apparatus is described as an example of a structure in which paper rolls Pa and Pb are arranged on two roll bearing seats 5a and 5b. However, the structure of the image forming apparatus to which the present invention is applied is not limited to this. For example, the image forming apparatus may also be provided with one roll bearing seat.

[0050] Furthermore, in the above description, parts and components related to the two paper rolls Pa and Pb are distinguished by using suffixes "a" and "b" (e.g., roll bearing housings 5a and 5b) for description. Hereinafter, the suffixes "a" and "b" are omitted unless it may be necessary to distinguish parts and components.

[0051] Here, a comparison method of setting the paper roll is described.

[0052] Figure 3A , 3B , 3C, 3D, and 3E are diagrams for explaining comparative methods of setting paper rolls, respectively.

[0053] Flanges (flange members) 77 are provided at both ends in the width direction of the paper roll Pr, and each reel 1 (reel 1a and reel 1b) is provided on the flanges 77. The user mounts the paper roll provided with the reel 1 (or reel 1a and reel 1b) on the receiving portion (roll bearing seat) of the paper feeding device of the image forming apparatus (see Figure 3A ).like Figure 3B As shown, after finding the leading end of the paper roll, the user holds the paper roll with both hands and holds (does not lose) the leading end of the paper roll, and then rotates the paper roll so that the leading end of the paper faces the user (in other words, faces the front side of the image forming apparatus 80). The user then places the leading end of the paper at a position between the guide plates located behind the paper roll, and inserts the leading end of the paper while rotating the paper roll (see FIG. Figure 3C ). The guide plate includes an upper guide plate and a lower guide plate made of a transparent material, through which the paper can be seen. The user rotates the paper roll toward the far end of the image forming device 80 so that the front end of the paper roll reaches the upper part of the lower guide plate. When the user inserts the paper roll into the far end behind the lower guide plate, the paper roll is fixed in the housing of the image forming device and is pulled into the interior of the image forming device.

[0054] like Figure 3C As shown in the figure, since the guide plate for inserting the front end of the paper is located behind the paper roll, the guide plate is hidden by the paper roll and is difficult to see from the front of the image forming apparatus. In addition, since the guide plate is made of a transparent material, even when the user thinks that the paper is inserted between the two guide plates, the paper may actually be placed on top of the upper guide plate, which requires the user to re-place the paper to the correct position. In addition, when the guide plate is not made of a transparent material, it is difficult to confirm whether the paper is inserted between the two guide plates.

[0055] Furthermore, the front end of the paper roll needs to be inserted as evenly as possible, so the user must be careful. In addition, when the front end of the paper is not inserted evenly, the paper in this uneven state may be fed obliquely, resulting in skew. Therefore, the action can be re-performed to prevent the occurrence of paper jams.

[0056] In addition, if Figure 3D and 3EAs shown in the figure, in an image forming apparatus in which paper rolls are vertically arranged in two stages, there may be a case where when one paper roll is set to the lower stage, another paper roll has been set to the upper stage. In this case, even if the front end of the paper roll is inserted between the guide plates, the guide plates are difficult to see due to the paper roll already set to the upper stage, thereby increasing the difficulty of setting the paper roll and the possibility of the paper being inserted obliquely.

[0057] In order to solve this inconvenience, the paper feeding device according to an embodiment of the present invention has a structure for detecting the front end of the paper of the paper roll. By detecting the step difference (height) of the front end of the paper, the front end of the paper P can be detected, so that the paper is fed into the paper feeder (paper feeding part). The paper feeder is a device that feeds the paper of the paper roll to the supply target. For example, the paper feeder is Figure 2 The paper conveying roller pair 6 or the paper conveying path 9 shown in FIG.

[0058] Figure 4 It means in Figure 1 A side view of a main portion of an example of a structure of a paper feeding device according to an embodiment of the present invention in an image forming apparatus 80.

[0059] The paper feed device 90 includes at least an arm 91, a roller 92, a sensor 93, and a pair of paper conveying rollers 6 as a paper feeder. The paper feed device 90 preferably further includes an entrance guide plate 95.

[0060] exist Figure 4 , a dotted line indicates the position of the paper roll Pr when the user sets the paper roll Pr in the paper feeding device 90. The paper roll Pr is rotatably supported by the module assembly based on the center (axis) of the paper roll Pr.

[0061] The arm (guide plate) 91 serves as a support for the paper roll Pr and is rotatable around the rotation center 911. The arm 91 is pressed toward the end of the axis of the rotation center 911 that faces the paper roll Pr by a biasing member (such as a spring). Therefore, even if the diameter of the paper roll Pr changes, the arm 91 can contact the outer diameter of the paper roll Pr. The white arrow indicates the moving direction of the arm 91, more specifically, the rotation direction of the arm 91.

[0062] Furthermore, the arm 91 has a roller 92 and a sensor 93 at the other end of the axis of the rotation center 911. Since the arm 91 is pressed toward the paper roll Pr, the supporting roller 92 and the sensor 93 come into contact with the surface of the paper roll Pr.

[0063] The arm 91 serves as a guide plate to guide the paper P peeled or separated from the paper roll Pr in the paper conveying direction. The arm 91 has a shape (e.g., an arc shape) along the outer diameter of the paper roll Pr at the portion (end portion) where the paper roll Pr is set. Due to the shape of the arm 91, when the paper roll Pr is set, the paper roll Pr is reliably held (does not fall off). The arm 91 also serves as a guide plate to guide the paper P peeled or separated from the paper roll Pr in the paper conveying direction. Figure 2 The paper roll receiving seat 8 shown in FIG.

[0064] The arm 91 as a bracket is also used as a guide plate for guiding the paper roll Pr, so that the number of parts can be reduced and the cost can be suppressed.

[0065] The roller 92 and the sensor 93 are arranged substantially toward the center of the paper roll Pr, that is, toward the axial center of the paper roll Pr, regardless of the diameter of the paper roll Pr.

[0066] The roller 92 is disposed apart from the sensor 93 in the circumferential direction of the paper roll Pr, so that the roller 92 and the sensor 93 are spaced apart from each other (at different positions) in the circumferential direction of the paper roll Pr.

[0067] The sensor 93 has a detection accuracy capable of detecting the step (thickness) at the leading end of the paper roll Pr.

[0068] The entrance guide plate 95 guides the paper P peeled or separated from the paper roll Pr in the paper conveying direction. Figure 4 In the structural example of , when the paper P is conveyed in the paper feeding action (positive rotation of the paper roll Pr), the arm 91 as the guide guides the paper P on the upstream side in the paper feeding direction, and the entrance guide 95 guides the paper P on the downstream side in the paper feeding direction. In other words, the arm 91 is provided upstream of the entrance guide 95 in the rotation direction of the paper roll in the paper feeding action.

[0069] Next, functional control of the paper feeding device 90 will be described. Figure 5 is a block diagram showing a functional example of a paper feeding device according to an embodiment of the present invention.

[0070] The controller 110 performs overall control of the paper feeding device 90. Note that Figure 5 1 and 140. The controller 110 controls the sensor 93 and the motor drive circuits 120 and 140, and other functional blocks are omitted. The functions of the controller 110 may be controlled by the controller 100 (see FIG. 1 ) that controls the overall control of the image forming apparatus 80. Figure 2 )implement.

[0071] The controller 110 includes, for example, a central processing unit (CPU), a random access memory (RAM), and a read only memory (ROM).

[0072] The CPU executes various programs and controls the entire image forming apparatus 80 according to the arithmetic processing and control programs.

[0073] RAM is a volatile storage medium used to read and write information at high speeds, and acts as a work area when the CPU is executing programs.

[0074] ROM is a read-only nonvolatile storage medium in which various programs and control programs are stored.

[0075] The motor driving circuit 120 drives the motor under the control of the controller 110 , thereby driving the paper roll driver 130 .

[0076] The paper roll driver 130 rotates the paper roll Pr in a forward direction or a reverse direction. The paper roll driver 130 includes, for example, a paper roll rotating motor.

[0077] The motor driving circuit 140 drives the motor under the control of the controller 110 , thereby driving the paper transport driver 150 .

[0078] The paper conveying driver 150 drives the paper conveyor 160 .

[0079] The paper conveyor 160 is a paper conveyor that conveys the paper P, for example, a paper conveying roller pair 6 .

[0080] Next, an example of the operation of setting the paper roll Pr will be described. Figure 6 1 is a flowchart showing an example of an operation of setting a paper roll in a paper feeding device according to an embodiment of the present invention.

[0081] For example, when the controller 110 detects that a paper roll Pr is provided in the paper feeding device 90 according to the detection result of the sensor 93 (step S11), the controller 110 controls the motor driving circuit 120 to drive the paper roll driver 130 to rotate the paper roll Pr in the reverse direction. The controller 110 turns on the paper roll rotating motor (paper roll driver 130) to rotate the paper roll Pr in the direction of winding the paper in the reverse action of the paper, that is, to perform reverse rotation (step S12). Then, the sensor 93 starts to detect the front end of the paper roll Pr (step S13). When the sensor 93 detects the front end of the paper roll Pr, the controller 110 turns off the motor driving circuit 120, turns off the paper roll rotating motor at the position where the front end of the paper roll stops (step S14), and then turns on the paper roll rotating motor to rotate the paper roll Pr in the positive direction (positive rotation) of the paper conveying direction to feed the front end of the paper roll Pr in the paper conveying direction (step S15). The motor driving circuit 140 rotates the paper conveyor 160 to convey the leading end of the paper P into the motor driving circuit 140 (step S16 ).

[0082] Next, a configuration example of the arm 91 as a bracket and an operation example of detecting the leading end of the paper roll will be described.

[0083] Fig. 7A , 7B 7C are diagrams showing an example of the structure of the arm 91 according to an embodiment of the present invention. Specifically, Fig. 7A is a perspective view showing an example of the arm 91, Figure 7B is a schematic diagram showing the appearance of the sensor 93, Figure 7C 1 is a side view showing an example in which the sensor 93 includes an actuator and a side plate.

[0084] In the action of the sensor 93 detecting the leading end of the paper roll (reverse rotation), the roller 92 is provided on the upstream side of the arm 91 in the paper conveying direction, and the sensor 93 is provided on the downstream side of the arm 91 in the paper conveying direction. In other words, the sensor 93 is provided on the downstream side of the roller 92 along the paper conveying direction, that is, the rotation direction of the paper roll Pr.

[0085] The sensor 93 includes an encoder sensor including, for example, an actuator 931 and a slit 932 in the actuator 931. The actuator 931 is disposed between two side plates 933 constituting a sensor housing. A shaft 934 is mounted in a bearing of the side plates 933 and is rotatable around the shaft 934. The actuator 931 has an asymmetric shape centered on the shaft 934, for example, Figure 7C shown.

[0086] The sensor 93 has a light emitting part and a light receiving part, and detects the leading end of the paper roll Pr by counting the number of lights transmitted from the light emitting part to the light receiving part through the slit 932 of the actuator 931, that is, by counting the number of signal waveforms.

[0087] exist Fig. 7A , 7B In the structural examples of 7C and 7C, there are two rollers 92, and the sensor 93 is arranged between the two rollers 92. By arranging the sensor 93 between the rollers 92, the warping of the front end of the paper roll Pr can be reliably pressed. In this way, the output of the sensor 93 does not change due to the thickness, rigidity and curling state of the paper, so the front end of the paper can be reliably detected. In addition, since each roller 92 and the sensor 93 are arranged to be spaced apart from each other in the circumferential direction of the paper roll, even if there is, for example, a local scratch, the possibility that the scratch extends on the roller 92 and the sensor 93 is small. Therefore, it is difficult to make an erroneous detection of the front end of the paper P.

[0088] In the following description, two or more rollers 92, that is, a plurality of rollers, are also referred to as rollers.

[0089] Fig. 8A , 8B 8A and 8C are diagrams showing examples of the operation of detecting the leading end of the paper roll Pr. 9A and 9B are diagrams for explaining differences caused by the position of the roller 92 relative to the sensor 93, respectively.

[0090] Fig. 8A , 8B 8C shows the state when the front end of the paper roll Pr passes through the roller 92 and the sensor 93. More specifically, Fig. 8A This is the state before the front end of the paper roll Pr passes through the roller 92. Figure 8B It is the state when the front end of the paper roll Pr passes through the roller 92 and does not reach the sensor 93. Figure 8CThis is the state after the leading end of the paper roll Pr passes the sensor 93 .

[0091] Fig. 9A and 9B The state when the front end of the paper roll Pr is detected is shown to show the difference in the slack of the paper roll Pr. More specifically, Fig. 9A The roller 92 is arranged downstream of the sensor 93 in the paper conveying direction. Fig. 9B This is a state in which the roller 92 is disposed upstream of the sensor 93 in the paper conveying direction.

[0092] The sensor 93 and the roller 92 are arranged close to each other and spaced apart from each other, that is, there is a gap in the circumferential direction of the paper roll Pr. According to this structure, since the roller 92 is located upstream of the sensor 93 in the paper conveying direction, before the sensor 93 detects the front end of the paper roll Pr, the roller 92 presses the front end of the paper roll Pr ( Fig. 8A According to this structure, when the tip of the sensor 93 is in close contact with the surface of the paper roll Pr, Fig. 9B As shown, since the sensor 93 detects the step (thickness) on the surface of the paper roll Pr as the front end of the paper roll Pr, the output of the sensor 93 (i.e., the detection result of the sensor 93) will not change due to the thickness, rigidity and curling state of the paper, and the sensor 93 can reliably detect the front end of the paper roll Pr.

[0093] Note that in the example of the present embodiment, the roller 92 (or rollers 92) is disposed upstream of the sensor 93 in the paper conveying direction, but Fig. 9A As shown, a structure in which the roller 92 and the sensor 93 are arranged in opposite positions can be used to detect the front end of the paper roll Pr. However, it is preferable that the roller 92 is arranged upstream of the sensor 93 so as to more reliably press the tilting of the front end of the paper roll Pr until the front end of the paper roll Pr is detected.

[0094] Furthermore, as shown in FIG. 7 , since two rollers 92 are provided and the sensor 93 is disposed between the rollers 92 , the warping of the leading end of the paper roll Pr can be suppressed more reliably compared to a configuration having one roller 92 .

[0095] In addition, since the paper feeding device 90 according to an embodiment of the present invention has a structure in which each roller 92 and sensor 93 are arranged apart from each other (with displacement) in the circumferential direction of the paper roll Pr, even if there are, for example, local scratches, the possibility of the scratches extending on the roller 92 and the sensor 93 is small. Fig. 10A and 10B are example diagrams showing signal waveforms detected by the sensor. More specifically, Fig. 10A is an example of a signal waveform when the leading end of a paper roll is detected. Fig. 10B is an example showing a signal waveform when a raised streak or a scratch is detected.

[0096] 7, when the front end of the paper roll Pr is normally detected (in the case where the front end of the paper P passes), the formation is as follows: Fig. 10A The signal waveform is shown.

[0097] On the other hand, when strip-shaped raised streaks (scratches) are formed on the surface of the paper roll Pr, Fig. 10B The signal waveform shown in has a rise and fall different from the signal waveform for detecting the front end of the paper roll Pr. Therefore, the controller 110 distinguishes the detection result of the sensor 93 into a normal signal waveform for detecting the front end of the paper roll and a signal waveform for detecting scratches, thereby excluding the raised streak (scratch) as a foreign matter (not the front end of the paper roll). Therefore, the detection of the front end of the paper roll and the raised streak (scratch) is almost impossible to be mistaken.

[0098] Next, detection of depressed streaks (depressed scratches) will be described. Fig.11 This is a diagram for explaining a situation where a concave streak (scratches) is formed on the surface of a paper roll.

[0099] In the case of a concave stripe (scratch), the shape of the tip of the sensor 93 is generally larger than the concave stripe (scratch), and the edge of the scratch does not have the same acute angle as the angle of the front end of the paper roll. Therefore, the stripe or scratch is not detected. By making the shape of the actuator larger than the concave stripe (scratch), the sensor 93 does not detect the concave stripe (scratch), so the detection is not erroneous. Thus, the accuracy of detection can be achieved.

[0100] according to Figures 4 to 11 The structure shown in the figure directly detects the front end of the paper roll. Therefore, the output (detection result) of the sensor 93 does not change due to the thickness, rigidity or curled state of the paper, so the sensor 93 can detect the front end of the paper roll Pr with reliable detection accuracy. In addition, the setting of the paper roll can be automatically completed by the simple action of the user placing the paper roll on the paper feeding device 90. This structure reduces manual actions and prevents skew and paper jams caused by guide failure.

[0101] As described above, the configuration example of the paper feeding device according to the embodiment of the present invention has been described. However, the sensor 93 is preferably configured as described below.

[0102] Fig. 12A and 12B The diagrams respectively show the friction load applied to the surface of the paper roll when the actuator of the sensor contacts the surface of the paper roll. When the actuator 931 of the sensor 93 contacts the surface of the paper roll, a friction load is generated at the contact portion as the paper roll rotates.

[0103] exist Fig. 12AThe "normal" direction (positive rotation) shown in represents the rotation direction in the paper conveying action when the paper roll Pr is conveyed in the paper conveying direction. Fig. 12A The "reverse" direction (reverse rotation) shown in ref erence to FIG. 1 represents the rotation direction when the leading end of the paper roll Pr is detected.

[0104] In the “reverse rotation” direction, a “load during reverse rotation” is generated on the actuator 931 , so that a force is applied in a direction in which the actuator 931 bites the paper roll Pr.

[0105] On the other hand, in the “forward rotation” direction, when a “load in forward rotation” is applied to the actuator 931, the actuator 931 rotates around the shaft 934 as a rotation fulcrum to reduce the load. In other words, when a load is applied to the actuator at a portion where the actuator contacts the paper roll Pr while the paper roll Pr is rotating during the paper conveying operation, the actuator moves in a direction to reduce the load applied to the actuator.

[0106] Here, detecting the leading end of the paper roll Pr in the “reverse rotation” direction refers to an action when the paper roll Pr is set to the paper feeder of the paper feeding device. When compared with the rotation direction of the paper roll Pr and the action in the “forward rotation” direction (e.g., paper feeding action and printing action), the time required for the action in the “forward rotation” direction is much longer. When a large force is applied to the actuator 931 in the “forward rotation” direction, an action failure is more likely to occur due to damage to the sensor 93 and wear of the actuator 931. Therefore, the paper feeding device has a structure that can avoid (eliminate) the load when the paper roll rotates in the “forward rotation” direction, thereby preventing damage and action failure.

[0107] Fig.13 1 is an exemplary diagram for explaining that the actuator has a distal end that contacts the paper roll and is provided with a rotating roller serving as a rotating body.

[0108] Even when the actuator 931 of the sensor 93 has a friction load with the paper roll Pr, the roller 935 can be rotated to reduce the load on the actuator 931, thereby preventing damage and operation failure.

[0109] Note that this structure example illustrates a structure in which the actuator rotates, but is not limited to this structure example. For example, a structure in which the actuator moves vertically and a rotatable roller is provided at the end can also be applied to the present invention.

[0110] Next, a modification of the support body including the sensor and the roller will be described. Figure 4 The structural example shown in FIG. 1 includes an arm 91 as a support body, but Fig.14 The structural example shown in includes another support body different from the arm 91 (or the guide plate).

[0111] Fig.14This is a diagram for explaining an example in which the sensor 93 and the roller 92 are provided near an entrance guide 95 for paper conveyance by the paper conveying device 90A.

[0112] The paper feeding device 90A has substantially the same structure as the paper feeding device 90, except that the paper feeding device 90A includes an arm 91A instead of an arm 91A. Figure 4 The arm 91A has a plurality of support arms 91A and a bracket 97 supporting the sensor 93 and the roller 92 (or rollers 92). The bracket 97 is disposed near the inlet guide plate 95 and upstream of the inlet guide plate 95 in the "reverse rotation" direction, i.e., in the direction in which the paper roll Pr rotates in the reverse rotation action. Figure 4 The arm 91 shown in FIG. 1 has the same structure, except that the arm 91A does not include the sensor 93 .

[0113] With this structure, after the roller 92 (or rollers 92) supported by the bracket 97 and the sensor 93 detect the leading end of the paper roll Pr, the leading end of the paper roll Pr immediately stops at a position between the entrance guide 95 and the arm 91A, so that in the "forward rotation" action, the leading end of the paper roll Pr is fed into the paper feed roller pair 6. Therefore, the forward rotation action starts in the shortest time from the detection of the leading end of the paper roll.

[0114] The support 97 is disposed toward the approximate center of the paper roll Pr. With this structure, even if the diameter of the paper roll Pr changes, the support 97 is in continuous contact with the surface of the paper roll Pr.

[0115] As described above, since the image forming apparatus that feeds paper in a roll form includes the paper feeding device according to the embodiment of the present invention, the user sets the paper roll to the image forming apparatus through a simple action, and the paper thickness sensor (e.g., encoder sensor) automatically detects the front end of the paper roll, and the front end of the paper roll can be fed to the paper feeder of the paper feeding device. Therefore, the manual action required to set the paper roll is omitted, and the paper is reliably inserted into the paper feeder, which can prevent the paper from being tilted or inserted into the paper feeder at a certain angle.

[0116] In addition, since the paper feeder according to the embodiment of the present invention detects the front end of the paper roll while the front end of the paper roll is in close contact with the surface of the paper roll, the front end of the paper roll can be reliably detected regardless of the thickness, rigidity, and curling state of the paper. In addition, when setting the paper roll, the deviation of manually inserting the paper is eliminated, and therefore, the front end of the paper roll is reliably inserted into the paper feeder.

[0117] The present invention is not limited to the specific embodiments described above, and many additional modifications and changes can be made according to the teachings within the technical scope of the attached claims. Therefore, it should be understood that the disclosure of this patent specification can be implemented by those skilled in the art in other ways than those specifically described herein, and such modifications and alternatives are within the technical scope of the attached claims. Such embodiments and their variations are included in the scope and gist of the embodiments of the present invention, and are included in the embodiments described in the claims and their equivalent scope.

[0118] The effects described in the embodiments of the present invention are listed as examples of preferred effects derived from the present invention, and thus are not limited to the embodiments of the present invention.

[0119] The above embodiments are presented as examples of implementing the present invention. The above embodiments are not intended to limit the scope of the present invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions or changes can be made without departing from the gist of the present invention. These embodiments and their variations are included in the scope and gist of the present invention, and are included in the scope of the present invention described in the claims and their equivalents.

[0120] Any of the actions described above may be performed in various other ways, for example, in an order different from that described above.

[0121] This patent application is based upon and claims the benefit of priority from Japanese Patent Application No. 2020-007309 filed in the Japan Patent Office on January 21, 2020, the disclosure of which is incorporated herein in its entirety by reference.

[0122] Reference numerals list

[0123] 6 Paper feed roller pair

[0124] 90, 90A paper feeder

[0125] 91, 91A Arm

[0126] 92 Rollers

[0127] 93 Sensors

[0128] 95 entrance guide

[0129] 97 Bracket

[0130] 100, 110 controller

[0131] 120, 140 motor drive circuit

[0132] 130 Paper roll drive

[0133] 150 Paper transport driver

[0134] 160 Paper feeder

[0135] 911 Rotation Center

[0136] 931 Actuator

[0137] 932 Slit

[0138] 933 Side Panel

[0139] 934 Axis

[0140] Citation List

[0141] Patent Literature

[0142] [Patent Document 1] JP-2018-150107-A

Claims

1. A paper feeding device, configured to feed paper from a paper roll, the paper feeding device comprising: sensor; Roller; as well as a support on which the sensor and the roller are arranged, The bracket supports the sensor and the roller so that the sensor and the roller contact the surface of the paper roll. The sensor and the roller are oriented toward the axial center of the paper roll, The roller is arranged separately from the sensor in the circumferential direction of the paper roll, the roller includes two or more rollers in the width direction of the paper roll, and the sensor is arranged between the two or more rollers. The sensor has a detection accuracy capable of detecting a step at the front end of the paper roll, Among them, in the action of the sensor detecting the front end of the paper roll, the sensor is set downstream of the roller in the rotation direction of the paper roll, and detects the step of the front end in a state of close contact with the surface of the paper roll in a state where the front end is wound on the surface of the paper roll.

2. The paper feeding device according to claim 1, in, The sensor includes an encoder sensor.

3. The paper feeding device according to claim 1 or 2, in, The support is a guide plate configured to guide the paper fed from the paper roll.

4. The paper feeding device according to claim 1 or 2, further comprising an entrance guide plate configured to guide the paper in a paper conveying direction, in, During the paper feeding operation, the support is disposed upstream of the inlet guide plate in the rotation direction of the paper roll.

5. The paper feeding device according to any one of claims 1 to 4, in, The sensor comprises: Multiple side panels; and an actuator rotatably disposed between the side plates, The actuator is configured to move in a direction to reduce the load on the actuator when a load is generated due to contact between the actuator and the paper roll when the paper roll rotates during a paper feeding operation.

6. The paper feeding device according to claim 5, in, The actuator has a top end with a rotating body.

7. An image forming device comprising: an image forming device configured to form an image on paper; as well as A paper feeding device according to any one of claims 1 to 6.

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