JP5900040B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile, a copying apparatus, a plotter, and a complex machine of these, for example, a liquid discharge recording type image forming apparatus using a recording head composed of a liquid discharge head (droplet discharge head) for discharging droplets An ink jet recording apparatus or the like is known.

  In such an image forming apparatus, as a recording medium on which an image is formed, there is an apparatus that uses roll paper that is a long roll-shaped medium wound around a core member (tube) in a roll shape.

  Conventionally, the roll paper is provided with a back tension variable means that can apply a back tension in a direction opposite to the roll paper conveyance direction and can change the magnitude of the back tension, and the roll paper is removed according to the detection signal of the width detection means. There is known one that adjusts the distribution in the width direction of the effective conveying force in accordance with the width of the roll paper by changing the back tension at the time of conveyance (Patent Document 1).

JP 2009-256061 A

  By the way, it is possible to dispose paper feed rollers as transport means for transporting roll paper in a direction orthogonal to the roll paper transport direction so that many sizes of roll paper can be transported with a small number of paper feed rollers. Conceivable.

  In this case, a conveyance force is always applied to the side of the roll paper on which the paper feed roller is disposed, but the conveyance force applied to the side on which the paper feed roller is not disposed becomes weak and slack occurs.

  However, since the conventional back tension applying means only applies the back tension in one system, there is a problem that it is difficult to set the back tension delicately, for example, the back tension becomes too large or too weak. is there.

  The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to easily adjust and set the back tension.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
A transport rotating body for feeding the medium fed from a roll body in which a long medium is wound around a core member ;
Conveying means for conveying the medium to the image forming means on the downstream side of the conveying rotating body ;
Load applying means for applying a load in the direction opposite to the medium conveyance direction to the roll body,
The transport rotator is arranged to be biased in a direction orthogonal to the medium transport direction,
The load applying means includes
First load generating means for generating a load in a direction opposite to the medium conveying direction with respect to the spool shaft holding the roll body;
A rotation member that rotates by rotation of the spool shaft in a separate system from the first load generation unit, and a second load generation unit that includes a unit that applies a load to the rotation member ,
When the medium is transported, a load on the roll body is generated by a combination of the first load generating unit and the second load generating unit .

  According to the present invention, it is possible to easily adjust and set the back tension.

1 is an external perspective view illustrating an example of an image forming apparatus according to the present invention. 2 is a schematic side view of the apparatus. FIG. It is principal part plane explanatory drawing of the mechanism part of the apparatus. FIG. 6 is an explanatory plan view for explaining an arrangement position of a conveyance roller pair. It is front explanatory drawing which shows an example of a back tension mechanism. It is a plane explanatory drawing similarly.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. An example of an image forming apparatus according to the present invention will be described with reference to FIGS. FIG. 1 is an external perspective view of the image forming apparatus, FIG. 2 is a schematic side view of the apparatus, and FIG.

  This image forming apparatus is a serial type image forming apparatus, and includes an apparatus main body 101 and a paper feeding device 102 disposed below the apparatus main body 101.

  Inside the apparatus main body 101, guide rods 1 and guide stays 2, which are guide members, are spanned on both side plates (not shown), and a carriage 5 is placed on these guide rods 1 and guide stays 2 in the direction of arrow A (main scanning direction, It is held so as to be movable in the carriage movement direction).

  A main scanning mechanism that moves and scans the carriage 5 is disposed on one side in the main scanning direction, a driving pulley 7 that is rotationally driven by the driving motor 6, and on the other side in the main scanning direction. The driven pulley 8 and a timing belt 9 that is a pulling member wound between the drive pulley 7 and the driven pulley 8 are provided.

  As shown in FIG. 3, a plurality of (here, five) liquid ejections eject droplets of black (K), yellow (Y), magenta (M), and cyan (C). The recording heads 11a to 11e in which the head and the head tank for supplying the liquid to the head are integrated (referred to as “recording head 11” when not distinguished from each other) are sub-scanned with a nozzle row composed of a plurality of nozzles orthogonal to the main scanning direction. The droplets are mounted with their droplet discharge directions facing downward.

  Here, the recording head 11a and the recording heads 11b to 11e are arranged by shifting the position of one head (one nozzle row) in the sub-scanning direction that is a direction orthogonal to the main scanning direction. Each of the recording heads 11a to 11e has two nozzle rows. The recording heads 11a and 11b eject black droplets having the same color, and the recording heads 11c to 11e eject magenta (M), cyan (C), and yellow (Y) droplets, respectively.

  As a result, monochrome images can be formed with a width of two heads in one scan (main scan) using the recording heads 11a and 11b, and color images are formed using, for example, the recording heads 11b to 11e. be able to.

  Ink of each color is supplied to the head tank of the recording head 11 through the supply tube 16 from ink cartridges 10k, 10c, 10m, and 10y, which are main tanks that are replaceably attached to the apparatus main body 101. At this time, ink is supplied from one ink cartridge 10k to the two recording heads 11a and 11b that discharge droplets of the same color.

  On the other hand, in the recording area of the main scanning area of the carriage 5, a roll paper 120 is fed from a paper feeding device 102 to be described later, and a direction perpendicular to the main scanning direction of the carriage 5 (sub-scanning direction, paper It is intermittently conveyed in the conveyance direction (arrow B direction).

  The transport unit 21 includes a transport roller 23 that transports the roll paper 120 that is a roll-shaped medium fed from the paper feeder 102, a pressure roller 24 that is disposed opposite the transport roller 23, and a plurality of suction holes. A conveyance guide member 25 and a suction fan 26 as a suction unit that performs suction from a suction hole of the conveyance guide member 25 are provided.

  As shown in FIG. 2, a cutter 27 serving as a cutting means for cutting the roll paper 120 on which the image is formed by the recording head 11 at a predetermined length is disposed on the downstream side of the conveying means 21.

  The cutter 27 is attached to a wire or a timing belt 28, for example. The timing belt 28 is wound around a driving pulley driven by a driving motor (not shown) and a driven pulley, and the timing belt 28 is moved in the main scanning direction by the driving motor via the driving pulley. To cut the paper into a predetermined length.

  Further, a maintenance / recovery mechanism 30 that performs maintenance / recovery of the recording head 11 is disposed on one side of the carriage 5 in the main scanning direction on the side of the conveyance guide member 25, and recording is performed on the side of the conveyance guide member 25 on the other side. Empty discharge receptacles 34 that perform empty discharge for discharging liquid droplets that do not contribute to image formation from the head 11 are respectively disposed.

  The maintenance / recovery mechanism 30 includes a first maintenance / recovery unit 31 held by the frame member of the apparatus main body 101, and a second maintenance / recovery unit 32 held by the frame member of the maintenance / recovery mechanism 30 so as to be capable of reciprocating in the sub-scanning direction. have. The second maintenance / recovery unit 32 is at the position shown in FIG. 2 when performing the maintenance / recovery of the recording head 11a, and moves to the same position in the sub-scanning direction as the first maintenance / recovery unit 31 when performing the maintenance / recovery of the recording heads 11b to 11e.

  The maintenance / recovery mechanism 30 includes, for example, a suction cap 41 and a moisturizing cap 42 that also serve as a moisturizing cap for capping the nozzle surface (surface on which the nozzle is formed) of the recording head 11, a wiper member 43 for wiping the nozzle surface, and image formation. And a blank discharge receiver 44 for receiving droplets (empty discharge droplets) that do not contribute to.

  The sheet feeding device 102 has upper and lower spool bearing bases 111A and 111B (hereinafter referred to as “spool bearing base 111” unless otherwise distinguished. The other members are the same, and the upper member is denoted by “A”. And the lower member is distinguished by adding “B” to the reference numeral. A roll body 112 is mounted on the spool bearing base 111 so that it can be fed out.

  The roll body 112 is obtained by winding a sheet (hereinafter referred to as “roll paper”) 120 that is a long medium around a tube 114 that is a core member in a roll shape. The roll body 112 is a general term for a member (a rolled medium 120 in a wound state) in which the tube 114 and the roll paper 120 are combined.

  Then, the roll body 112 mounted on the spool bearing base 111 is rotated to feed the roll paper 120 downstream along the guide member 130.

On the downstream side of the spool bearing base 111 in the delivery direction , a conveyance roller pair 131 is disposed as a conveyance rotation body that curves and feeds the roll paper 120 delivered from the roll body 112, and the conveyance roller pair 131 and the spool A driven roller 160 that is in contact with the upper surface of the roll paper 120 and is driven by the movement of the roll paper 120 is disposed between the bearing base 111 and a roll between the spool bearing base 111 and the conveying roller pair 131. A guide member 130 for guiding the lower surface of the paper 120 is disposed.

  By rotating the transport roller pair 131, the roll paper 120 fed out from the roll body 112 is transported in a stretched state between the transport roller pair 131, the driven roller 160, and the roll body 112, and passes through the transport roller pair 131. Then, it is fed between the conveying roller 23 and the pressure roller 24 of the conveying means 21.

  In the image forming apparatus configured as described above, the recording head 11 is moved while the carriage 5 is moved in the main scanning direction and the roll paper 120 fed from the paper feeding device 102 is intermittently fed by the conveying means 21. A required image is formed on the roll paper 120 by ejecting droplets by driving according to image information (printing information). Then, the roll paper 120 after image formation is cut to a predetermined length by the cutter 27 and discharged to a paper discharge tray (not shown) disposed on the front side of the apparatus main body 101.

  Next, the arrangement of the conveyance roller pair 131 will be described with reference to FIG. FIG. 3 is an explanatory plan view for explaining the same.

  As shown in FIG. 3, the conveyance roller pair 131 is arranged in a biased manner in a direction (also referred to as a width direction) orthogonal to the conveyance direction of the roll paper 120. That is, in this image forming apparatus, the roll roller 120 of all sizes is transported on the basis of one side in the direction orthogonal to the transport direction of the roll paper 120. Therefore, the transport roller 131 is the most usable. The roll paper 120 having a small size (denoted as a roll paper 120A shown by a broken line in the drawing) can be conveyed, for example, positioned near the center of the roll paper 120A.

  Therefore, when transporting a large-sized roll paper 120 (indicated as a roll paper 120B shown by a broken line in the figure), one side in the width direction of the roll paper 120B receives a transport force by the transport roller pair 131, but on the other side. Since there is no transport roller 131, slack occurs.

  As described above, when the roll paper 120 is transported with one side in the width direction slackened, wrinkles may occur when the roll paper 120 is transported by the transport roller 23 and the pressure roller 24.

  Next, the back tension mechanism (load applying means) of this image forming apparatus will be described with reference to FIGS. FIG. 4 is an explanatory front view of the back tension mechanism, and FIG. 5 is an explanatory plan view of the same.

  The back tension mechanism 300 includes first load generating means 301 and second load generating means 302.

  First, the first load generating unit 301 will be described.

  A rotation transmission mechanism 202 connected to the drive motor 200 is connected to the spool shaft 201 of the roll body 112. By controlling the rotation state of the drive motor 200, a load is applied to the spool shaft 201 of the roll body 112, and a back tension is applied to the roll paper 120 being conveyed. That is, the first load generating means 301 is configured by the drive motor 200 and the rotation transmission mechanism 201.

  Here, the rotation transmission mechanism 202 will be described. The spool shaft 201 mounted on the pipe 114 of the roll body 112 is provided with a driven gear 203 that rotates following the spool shaft 201. The driven gear 203 is connected to a one-way clutch 207 having a gear 206 through idle gears 204 and 205.

  A torque limiter 210 is provided along with the gear 209 on the same rotary shaft 208 as the one-way clutch 207. Although not shown, a rotary encoder that detects the amount of rotation of the rotary shaft 208 is disposed, and detects the remaining amount of the roll paper 120 by detecting the amount of rotation.

  The gear 209 is connected to the transmission gear 213, and is connected to a drive gear 216 of a drive motor 200 that is a drive unit that rotates and drives via an idle gear 215 provided on the rotation shaft 214 of the transmission gear 213. Although not shown, a rotary encoder that detects the rotation of the rotating shaft 214 is arranged to detect the rotational speed of the drive motor 200.

  In the first load generating means 301 configured as described above, the back tension is strong (reverse rotation) and medium (no power supply) by selecting the normal rotation, reverse rotation, or no-power supply state as the drive state of the drive motor 200. State) and weak (forward rotation).

  Briefly describing this point, when the back tension is set to the middle, the drive motor 200 is brought into a non-excited state. Thereby, when the roll body 112 is rotated in the feeding direction and the spool shaft 201 rotates, a load for rotating the spool shaft 201 from the rotation transmission mechanism 202 to the drive motor 200 is generated. It becomes the back tension to.

  Further, when the back tension is weakened, the drive motor 200 is driven forward so that the gear 209 rotates faster than the gear 206 of the one-way clutch 207. As a result, the gear 206 of the one-way clutch 207 is idled with respect to the rotating shaft 208, and the gear 206 of the one-way clutch 207 is rotated on the spool shaft 201 of the roll body 112 via the idle gears 204 and 205. However, a weak back tension is applied to the roll paper 120 as compared with when the drive motor 200 is not excited.

  When the back tension is increased, the drive motor 200 is driven in reverse. As a result, the rotation direction of the rotary shaft 208 by the drive motor 200 and the rotation direction of the gear 209 by the roll body 112 being fed out are reversed, so that an excessive torque exceeding the limit of the torque limiter 210 is generated and torque is transmitted. Is interrupted, the rotary shaft 208 rotates while sliding in the torque limiter 210, and the resistance force received by the rotary shaft 208 sliding in the torque limiter 210 becomes a load against the rotation of the spool shaft 201, and the roll paper 120 has a strong back tension. Is granted.

Next, the second load generating unit 302 will be described with reference to FIG.

  The second load generating unit 302 is a separate system from the first load generating unit 301 and includes a driven gear 251 that rotates following the spool shaft 201 and a driven gear 252 that is a rotating member that meshes with the driven gear 251. ing. Then, a spring member 253 (for example, a spring washer) that presses the driven gear 252 between a driven shaft 252 and a gear shaft 402 provided on a fixed portion (frame member or the like) 401 that rotatably supports the driven gear 252. Is provided.

  With this configuration, when the spool shaft 201 rotates, the second load generating means 302 generates a load by the driven gears 251 and 252 and pushes the driven gear 252 with the spring member 252. A load due to the heavy rotation of 252 is generated.

  Therefore, the back tension can be easily adjusted and set by setting the pressing force of the spring member 253.

  On the other hand, when only the first load generating means 301 is not provided with the second load generating means 302, various elements such as gears, torque limiters, and one-way clutches of the first load generating means 301 are provided. Must be set in advance, and delicate adjustment of the back tension cannot be easily performed, resulting in an increase in cost.

  In the present application, the “paper” is not limited to paper, but includes OHP, cloth, glass, a substrate, etc., and means a material to which ink droplets or other liquids can be attached. , Recording media, recording paper, recording paper, and the like. In addition, image formation, recording, printing, printing, and printing are all synonymous.

  The “image forming apparatus” means an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. “Formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply causing a droplet to land on the medium). ) Also means.

  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, for example, includes DNA samples, resists, pattern materials, resins, and the like.

  In addition, the “image” is not limited to a planar image, and includes an image given to a three-dimensionally formed image and an image formed by three-dimensionally modeling a solid itself.

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

10 Ink cartridge (main tank)
5 Carriage 11, 11a to 11e Recording head (liquid ejection head)
DESCRIPTION OF SYMBOLS 21 Conveying means 23 Conveying roller 24 Pressure roller 25 Conveying guide member 26 Suction fan 27 Cutter 101 Device main body 102 Paper feeding device 112, 112A, 112B Roll body 114 Pipe (core member)
120 Roll paper (medium, roll-shaped medium)
131 Conveying roller pair 300 Back tension applying mechanism 301 First addition generating means 302 Second load generating means 252 Driven gear (rotating member)
253 Spring member

Claims (2)

A transport rotating body for feeding the medium fed from a roll body in which a long medium is wound around a core member ;
A conveying unit disposed on the downstream side of the conveying rotating body and conveying the medium to the image forming unit ;
Load applying means for applying a load in the direction opposite to the medium conveyance direction to the roll body,
The transport rotator is arranged to be biased in a direction orthogonal to the medium transport direction,
The load applying means includes
First load generating means for generating a load in a direction opposite to the medium conveying direction with respect to the spool shaft holding the roll body;
A rotation member that rotates by rotation of the spool shaft in a separate system from the first load generation unit, and a second load generation unit that includes a unit that applies a load to the rotation member ,
The image forming apparatus according to claim 1, wherein when the medium is conveyed, a load on the roll body is generated by a combination of the first load generating unit and the second load generating unit . The rotating member is a gear that meshes with a gear of the spool shaft;
The image forming apparatus according to claim 1, wherein the means for applying a load to the rotating member is a spring member that presses the gear.

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