JP2014172753A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in which when a print is given to an adhesive surface side of a label, stable transportation cannot be performed as transporting force becomes insufficient.SOLUTION: An image formation apparatus includes: a driving motor 300 serving as a driving source for a transport roller 22 and a pressure roller 24 as a pair of transport rotary bodies; and a driving force switching transmission mechanism 301 which switches and selectively transmits the driving force of the driving motor 300 to the transport roller 22 and pressure roller 24. The driving force switching transmission mechanism 301 has a sun gear 311 to which the driving force is transmitted from the driving motor 300 through a gear 310 and a planetary gear 312 which revolves around the sun g ear 311 according to the rotating direction of the sun gear 311, and rotates on its axis in a revolution restricted state as the sun gear 311 rotates, and includes a gear 313 which can engage the planetary gear 313 and is coupled to the transport roller 22 and a gear 314 which can engage the planetary gear 313 and is coupled to the pressure roller 24, the driving force being transmitted to the side of the pressure roller 24 when a print is given to an adhesive surface of a printing medium 2.

Description

  The present invention relates to an image forming apparatus.

  Printing is performed on printing media that has an adhesive surface, such as tape and label paper without a backing sheet, and the adhesive surface does not have release paper (hereinafter also referred to as “linerless label paper”). 2. Description of the Related Art Image forming apparatuses such as label printers that are cut into lengths to form print medium pieces (hereinafter also referred to as “label pieces”) are known.

  In such an image forming apparatus, when the linerless label paper is transported by being sandwiched between the transport roller and the pressure roller, the surface of the transport roller is subjected to non-adhesive treatment so that the adhesive surface does not stick to the transport roller or the like. ing.

  Further, since the friction coefficient between the printing medium and the conveyance roller is reduced by performing the non-adhesion process on the surface of the conveyance roller, and it becomes easy to slip, it is necessary to increase the pressing force between the conveyance roller and the pressure roller.

  Here, conventionally, when a recording medium is introduced into a nip formed by a conveyance roller and a pressure member provided in contact therewith and conveyed while being sandwiched, an acceleration setting means for setting an acceleration during conveyance; There has been known one provided with a control unit that controls an acceleration setting unit so that the acceleration during conveyance of the recording medium can be varied according to the properties of the recording medium (Patent Document 1).

JP 2005-154113 A

  By the way, when printing on linerless label paper, printing is generally performed with the label substrate side as the printing surface and the adhesive surface as the surface in contact with the transport roller, but printing may also be performed on the adhesive surface as the printing surface. Done. If the label base material is transparent by printing on the adhesive surface, the printed surface can be protected without using a protective member.

  However, as described above, since the conveyance roller is subjected to non-adhesion treatment and has a small coefficient of friction, when the label substrate is adhered to the conveyance roller and conveyed with the adhesive surface as the printing surface, the friction coefficient is further increased. There is a problem that it becomes smaller and the transportability deteriorates.

  In this case, it is possible to further increase the pressing pressure between the pressure roller and the conveyance roller, but this causes problems such as the need for strength and an additional auxiliary member.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to enable conveyance with a stable conveyance force even when any surface of a print medium having surfaces with different friction coefficients is used as a printing surface. .

In order to solve the above problems, an image forming apparatus according to the present invention provides:
A pair of opposite conveying rotating bodies for conveying the print medium;
A drive source for the pair of conveying rotors;
A driving force switching transmission mechanism that selectively transmits the driving force of the driving source by switching to one conveyance rotating body and the other conveyance rotating body,
The driving force of the drive source is transmitted to the transport rotary body on the side where the frictional resistance with the print medium is increased in the transport rotary body pair.

  According to the present invention, even when any surface of a print medium having surfaces with different friction coefficients is used as a printing surface, it can be transported with a stable transport force.

It is side explanatory drawing which shows an example of the image forming apparatus which concerns on this invention. It is plane | planar explanatory drawing in the conveyance surface of the same apparatus. It is a typical explanatory view of the state where the drive transmission change mechanism in a 1st embodiment of the present invention is transmitting drive power to a conveyance roller. FIG. 6 is a schematic explanatory view of a state in which the drive transmission switching mechanism similarly transmits a driving force to the pressure roller. It is a typical explanatory view in the state where the drive transmission change mechanism in a 2nd embodiment of the present invention is transmitting drive power to a conveyance roller. It is front explanatory drawing of the adhesion surface detection means in 3rd Embodiment of this invention. It is a side explanatory view similarly.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of an image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory side view of the image forming apparatus, and FIG. 2 is an explanatory plan view of a conveying surface of the apparatus.

  The image forming apparatus includes a sheet feeding unit 101 that feeds the printing medium 2, an image forming unit 102 that is an image forming unit that forms an image on the printing medium 2, and the image forming unit 102. Then, a transport unit 103 that is a transport unit that transports the print medium 2 and a paper discharge transport unit 104 that transports the print medium 2 on which an image sent from the transport unit 103 is formed toward the discharge port 105 are arranged. Yes.

  The paper supply unit 101 is loaded with a roll body (roll-shaped print medium) 4 in which a print medium 2 such as a linerless label paper is wound around a core member 3 (which may be coreless) in a roll shape. The roll body 4 is rotatably supported by roll body support members 5 and 5.

  Here, the printing medium 2 is, for example, a continuous body in which an adhesive layer is formed on one surface of the medium substrate, and is wound around the core member 3 in a state where a mount (release paper, separator) is not attached to the adhesive surface. Linerless label paper.

  The image forming unit 102 includes a carriage 12 on which a recording head 11 including a liquid discharge head that discharges droplets onto the print medium 2 is mounted. The carriage 12 is movably held by the guide members 13 and 14 and reciprocated in a direction (main scanning direction) orthogonal to the conveyance direction of the print medium 2.

  Note that the recording head 11 is a head having two nozzle rows. By using two recording heads 11, black (K), cyan (C), magenta (M), yellow in four nozzle rows, respectively. The ink droplets of each color (Y) are ejected. However, the present invention is not limited to this, and a line-type head can also be used.

  Further, the image forming unit 102 is not limited to the form of the liquid ejection head, and various image forming units that form an image in contact and non-contact can be used.

  In the conveyance unit 103, a conveyance belt 21 is disposed below the recording head 11 as a belt-shaped member that is an adhesive surface protecting member formed in an endless belt shape. The conveyor belt 21 is wound around the conveyor roller 22 and the driven roller 23 so as to be able to move around. The surface of the conveyor belt 21 is subjected to non-adhesion processing.

  Although it is preferable that the conveyance belt 21 does not have adhesiveness to the adhesive surface, the adhesion to the adhesive surface is weak enough to prevent the print medium 2 from floating from the conveyance belt 21 during conveyance. It may have sex.

  A pressure roller 24 is disposed opposite the conveying roller 22. The surface of the pressure roller 24 is non-adhesive.

  The conveyance roller 22 and the pressure roller 24 constitute a conveyance rotation body pair. The printing medium 2 and a conveyance belt 21 that also serves as an adhesive surface protecting member are sandwiched between the conveyance roller 22 and the pressure roller 24 and conveyed to an image forming area by the recording head 11.

  By using such a transport means, the adhesive surface of the print medium 2 adheres to the transport path for transporting the print medium 2 and cannot be transported, or transport resistance becomes large and transport becomes unstable. There is no.

  Although not shown, the transport belt 21 is formed with a large number of holes, and the print medium 2 is adsorbed to the transport belt 21 by being sucked by a suction fan 28 disposed inside the transport belt 21. Note that, here, the print medium 2 is sucked onto the conveyor belt 21 by suction. However, the present invention is not limited to this, and the print medium 2 can be sucked with electrostatic force. Further, the adhesiveness of the adhesive surface of the printing medium 2 may be used to fix the printing medium 2 so as not to float from the conveyor belt 21.

  A paper guide 25 for preventing the printing medium 2 from floating is provided on the downstream side of the pressure roller 24, and a first pressure roller 26 is supported at the tip of the paper guide 25 so as to be driven to rotate. Further, a second pressure roller 27 that presses the print medium 2 against the conveyance belt 21 is disposed downstream of the conveyance roller 22 in the conveyance direction and upstream of the image forming area formed by the recording head 11. Thereby, it is possible to more reliably prevent the print medium 2 from floating from the conveyance belt 21 in the image forming area.

  In the paper discharge conveyance unit 104, the print medium 2 conveyed from between the conveyance belt 21 and the spur 29 facing the driven roller 23 is cut into a predetermined length to form a print medium piece (label piece) 200. A cutter unit 31 which is a cutting means is arranged. The cutter unit 31 includes a receiving member 37 that receives the print medium 2 sent from between the conveyance belt 21 and the spur 29, and a cutting blade (cutter) 38 that cuts the print medium 2. The cutter 38 performs main scanning. The print medium 2 is cut by moving in the direction.

  A paper discharge roller 32 is disposed on the downstream side of the cutter unit 31. A spur roller 33 is disposed facing the paper discharge roller 32. By these paper discharge roller 32 and spur roller 33, the label piece 200 cut by the cutter unit 31 is held in a state of being sent to the discharge port 105.

  A paper sensor 34 that detects the print medium 2 is disposed near the paper discharge roller 32.

  The surface of the paper discharge roller 32 that holds the label piece 200 is subjected to, for example, non-adhesive processing (processing in which the adhesive surface does not adhere) so that the adhesive surface of the label piece 200 can be peeled off. In this case, the discharge roller 32 itself can be formed of a peelable material.

  In the image forming apparatus configured as described above, the print medium 2 and the conveyance belt 21 are sandwiched together between the conveyance roller 22 and the pressure roller 24, and the conveyance roller 22 is rotationally driven. A desired image is formed by the recording head 11 of the image forming unit 102 while being conveyed by the conveying belt 21.

  Then, the conveyance belt 21 is peeled from the print medium 2 on which the image is formed, and only the print medium 2 is sent to the paper discharge conveyance unit 104, and is cut at a required position by the cutter unit 31 to be printed on the print medium piece (label piece). ) 200, and is held between the discharge roller 32 and the spur roller 33 in a state where it can be extracted from the discharge port 105 of the apparatus main body 100.

  Next, the drive transmission switching mechanism according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a schematic explanatory diagram of a state in which the drive transmission switching mechanism transmits a driving force to the conveying roller, and FIG. 4 is a schematic diagram of a state in which the drive transmission switching mechanism transmits a driving force to the pressure roller. It is explanatory drawing.

  In the present embodiment, the drive motor 300 serving as a drive source for the transport roller 22 and the pressure roller 24 as a pair of transport rotating bodies, and the driving force of the drive motor 300 are selectively switched to the transport roller 22 and the pressure roller 24. And a driving force switching transmission mechanism 301 that transmits to the motor.

  The drive force switching transmission mechanism 301 revolves around the sun gear 311 according to the rotation direction of the sun gear 311 and the sun gear 311 to which the drive force is transmitted from the drive motor 300 via the gear 310, and In the restricted state, it has a planetary gear 312 that rotates according to the rotation of the sun gear 311.

  A gear 313 that can mesh with the planetary gear 312 and is connected to the conveying roller 22, and a gear 314 that can mesh with the planetary gear 312 and that is connected to the pressure roller 24 are included.

  With this configuration, first, as shown in FIG. 3, when the sun gear 311 rotates in the direction of arrow A by the drive motor 300, the planetary gear 312 moves in the same direction as the rotation direction of the sun gear 311. Engage with the gear 313.

  Then, the planetary gear 312 rotates by receiving the rotation of the sun gear 311, so that the gear 313 rotates and the driving force is transmitted to the transport roller 22.

  As a result, the conveyance roller 22 is driven to convey the print medium 2.

  On the other hand, as shown in FIG. 4, when the sun gear 311 rotates in the direction of arrow B by the drive motor 300, the planetary gear 312 moves in the same direction as the rotation direction of the sun gear 311 and meshes with the gear 314.

  Then, the planet gear 312 rotates by receiving the rotation of the sun gear 311, so that the gear 314 rotates and the driving force is transmitted to the pressure roller 24.

  As a result, the pressure roller 24 is driven to convey the print medium 2.

  Therefore, when printing on the medium base side of the print medium 2, the print medium 2 is conveyed with the adhesive surface of the print medium 2 facing the conveyor belt 21, so that the driving force is transmitted to the conveyor roller 22 at this time. . That is, in this case, since the conveyance rotating body on the side where the frictional resistance with the print medium 2 is increased is the conveyance roller 22 (conveyance belt 21), the driving force is transmitted to the conveyance belt 21.

  On the other hand, when printing on the adhesive surface side of the print medium 2, the medium base surface of the print medium 2 is transported with the transport belt 21 side, and at this time, the driving force is transmitted to the pressure roller 24. Switch to. In other words, in this case, the conveying rotating body on the side where the frictional resistance with the printing medium 2 is increased is the pressure roller 24, and thus the driving force is transmitted to the pressure roller 24.

  As a result, even when printing on any surface of the print medium 2, it can be transported with a stable transport force. Moreover, the cost can be reduced by using a combination of a sun gear and a planetary gear.

  Note that when the driving force is transmitted to the pressure roller 24, the amount of winding of the print medium 2 around the driving roller 24 is reduced, so that the conveyance speed may be slower than the conveyance speed when the conveyance roller 22 is driven. preferable. Thereby, at least the amount of wrapping can maintain the conveyance accuracy.

  In this way, the opposite conveying rotator pair conveying the print medium, the driving source of the conveying rotator pair, and the driving force of the driving source are selectively switched to one conveying rotator and the other conveying rotator. A driving force switching transmission mechanism that transmits the driving force of the driving source to the conveying rotating body on the side of the conveying rotating body pair on which the frictional resistance with the printing medium is increased, so that the friction coefficient is different. Even when any surface of a print medium having a printing surface is used as a printing surface, it can be transported with a stable transport force.

  In addition, it can also be set as the structure which wound the conveyance belt or the presser belt between the pressure roller and the driven roller which is not illustrated also on the pressure roller side (the following embodiment is also the same).

  Next, a drive transmission switching mechanism according to a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic explanatory view showing a state in which the drive transmission switching mechanism transmits a driving force to the transport roller.

  The driving force switching transmission mechanism 301 of the present embodiment is engaged with a gear 321 to which driving force is transmitted from the driving motor 300 via a gear 310, and an arm 323 that meshes with the gear 321 and can rotate with the rotation center of the gear 321 as a fulcrum. And a switching gear 322 disposed so as to be displaceable.

  An actuator 324 such as a solenoid that displaces the arm 323 and meshes the switching gear 322 with the gear 313 or 314 is provided.

  With this configuration, as in the first embodiment, when printing on the medium substrate side of the print medium 2, the switching gear 322 is moved to the gear 313 side, and the driving force is transmitted to the transport roller 22. Switch to

  On the other hand, when printing on the adhesive surface side of the print medium 2, the switching gear 322 is moved to the gear 314 side to switch the driving force to the pressure roller 24.

  As a result, even when printing on any surface of the print medium 2, it can be transported with a stable transport force. Compared with the first embodiment, since the switching can be performed by the operation of the actuator, the configuration is simplified.

  Next, an adhesive surface detecting means in the third embodiment of the present invention will be described with reference to FIGS. FIG. 6 is an explanatory front view of the adhesive surface detecting means, and FIG. 7 is an explanatory side view of the same.

  In the present embodiment, an adhesive that is a detection unit that detects an adhesive surface that is a surface having a large friction coefficient among both surfaces of the print medium 2 between the roll body 4 and the nip portion of the conveyance roller 22 and the pressure roller 24. Surface detecting means 400 is arranged.

  Then, it is determined from the detection result of the adhesive surface detection means 400 whether the adhesive surface of the print medium 2 is on the conveying roller 22 side or the pressure roller 24 side, and the second embodiment is performed according to the determination result. The actuator 324 in the embodiment is driven to switch the switching gear 322 to the gear 313 or the gear 314 side.

  As a result, it is possible to automatically perform drive transmission switching without a user instruction.

  Here, the adhesive surface detection unit 400 includes detection rotating bodies 401 and 402 that contact the print medium 2 with each surface. The detection rotators 401 and 402 include a torque limiter and the like, and rotate following the print medium 2 when the load exceeds a certain load.

  In the detection rotating bodies 401 and 402, encoder wheels 403 and 404 are attached to the respective shaft portions 401a and 402a, and encoder sensors 405 and 406 for reading the encoder wheels 403 and 404 are arranged.

  Thereby, the read outputs of the encoder sensors 405 and 406 correspond to the rotation state of the detection rotating bodies 401 and 402, that is, the rotation amount, the rotation angle, and the rotation speed.

  At this time, the rotating body corresponding to the surface having a large friction coefficient of the print medium 2 has a larger follower rotation amount, rotation angle, and rotation speed, so that the adhesive surface is determined from the read output of the encoder sensors 405 and 406. Can be detected.

  Note that “image formation” in the present application not only applies an image having a meaning such as a character or a figure to a medium but also an image having no meaning such as a pattern or the like (simply a droplet). To land on the medium).

  The “ink” is not limited to an ink unless otherwise specified, but includes any liquid that can form an image, such as a recording liquid, a fixing processing liquid, or a liquid. Used generically.

  Further, the image forming apparatus includes both a serial type image forming apparatus and a line type image forming apparatus, unless otherwise limited.

2 Print medium 4 Roll body 11 Recording head 21 Conveyance belt 22 Conveyance roller (conveyance rotating body)
24 Pressure roller (conveying rotator)
DESCRIPTION OF SYMBOLS 100 Main body 101 Paper feeding part 102 Image forming part 103 Conveying part 104 Discharge conveying part 105 Discharge port 300 Drive motor 311 Sun gear 312 Planetary gear 313 Conveying roller side gear 314 Pressure roller side gear 322 Switching gear 324 Actuator 400 Adhesive surface Detection means

Claims (6)

A pair of opposite conveying rotating bodies for conveying the print medium;
A drive source for the pair of conveying rotors;
A driving force switching transmission mechanism that selectively transmits the driving force of the driving source by switching to one conveyance rotating body and the other conveyance rotating body,
An image forming apparatus, wherein a driving force of the driving source is transmitted to the transport rotary body on the side where frictional resistance with the print medium is increased in the transport rotary body pair.   The image forming apparatus according to claim 1, wherein a non-adhesion process is performed on a surface of the transport rotating body.   The driving force switching transmission mechanism is a state in which the sun gear rotated by receiving the driving force of the driving source, revolves around the sun gear according to the rotation direction of the sun gear, and the revolution is restricted. The image forming apparatus according to claim 1, further comprising a planetary gear that rotates according to the rotation of the sun gear. The driving force switching transmission mechanism is
A switching gear that is rotated by the driving force of the driving source;
The switching gear is arranged to be displaceable,
Drive means for displacing the switching gear;
The displacement of the switching gear by the driving means engages with a gear connected to the one transport rotator or a gear connected to the other transport rotator pair. The image forming apparatus described. Of the both sides of the printing medium, comprising a detecting means for detecting a surface having a large friction coefficient,
5. The image forming apparatus according to claim 4, wherein the driving force switching transmission mechanism is switched so as to transmit the driving force to a conveying rotating body on a side in contact with a surface having a large friction coefficient based on the detection result. The detection means includes a detection rotator that is arranged with the print medium to be conveyed interposed therebetween and rotates in accordance with the print medium,
The detection rotator rotates above a certain load,
6. The image forming apparatus according to claim 5, further comprising means for detecting a surface having a large friction coefficient from a rotation state of the detection rotating body.

Images