JP2007238235A - Sheet conveying device and recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily change pushing force to be applied to a driving roller by changing only lever ratio of a support for supporting a driven roller in a sheet conveying device. <P>SOLUTION: This sheet conveying device is provided with a roller support 44 for rotatably supporting the driven roller 32, which is arranged opposite to the driving roller 30 to be brought in contact with each other, in one end thereof and connected to an energizing means 46 in the other end thereof and supported freely to swing around a support position between both the ends thereof. A plurality of support points are provided in the longitudinal direction of the roller support, and lever ratio of the roller support can be changed by changing position of the support points to nearly fix the pinching pressure to be applied to a sheet passing through between the rollers 30 and 32. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet conveying apparatus and a recording apparatus including the sheet conveying apparatus.

  As a prior art of the present invention, the following Patent Document 1 includes a lever that adjusts the pressing force of the driven roller against the driving roller by rotating the pressure member, and even if the recording sheet has a large dimension in the thickness direction, A sheet conveying apparatus and an image forming apparatus including the sheet conveying apparatus that can appropriately obtain a holding force per unit area are disclosed.

  In this device, when using paper that is thicker or thinner than normal recording paper, the pressing force adjustment corresponding to the paper thickness is performed by rotating the lever. It is intended to avoid poor conveyance, and is suitable when the paper thickness is frequently changed.

JP 2004-106957 A

  In the conventional configuration described above, in order to obtain an appropriate pressing force, a sheet thickness detection unit, a display unit, and the like are provided, and a unit such as a rotation adjustment by a lever based on the display is required. It becomes complicated and causes a problem in apparatus cost.

  It is basically unnecessary to add the adjustment mechanism as described above in the usage mode in which the regular recording paper is always fed. Conventionally, in general, the driven roller is generally pressed against the driving roller with a constant force. A conveying device is used for this purpose.

  However, in this type of sheet conveying apparatus, the driven roller is made of a soft material such as an elastomer resin material that is softer than the driving roller, and is constantly applied with a pressing force. Repeated deformation force is applied to (paper contact area).

  Therefore, the accumulation of deformation force according to the number of sheets passing through causes a so-called sag phenomenon, which tends to cause problems such as idling and paper jams in the short period of time compared to the entire machine life. Each time, the inside of the machine had to be opened and maintenance such as removal of paper pieces and paper dust and cleaning work had to be performed.

  For example, it has been reported through endurance tests that the number of lifespan of the entire machine is acceptable up to 100,000 sheets of A4 paper, but the above-mentioned problems gradually appear and the number of maintenance increases as it passes through about 50,000 sheets. Has been.

  In order to fundamentally solve this phenomenon, replace the driven roller by calling a maintenance engineer from the product supplier, or by replacing the part with a strong spring as a pressing force biasing means. it can. However, since both of them require internal disassembly and reassembly with a new part, the maintenance cost becomes expensive.

  It should be noted that even if the driven roller is slightly slackened, the deterioration phenomenon is not so great as to replace it. Similarly, the spring maintains the same spring elasticity as in the initial state, and none of the springs have been replaced until now.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and an object of the present invention is to convey a sheet that can easily change the pressing force against the driving roller by changing only the lever ratio of the support that supports the driven roller. A device is provided.

  Another object of the present invention is to provide a recording apparatus that includes this type of sheet conveying device and that can easily change the pressing force associated with the sag phenomenon of a driven roller.

In order to achieve the above-mentioned object, the first aspect of the present invention is such that the driven roller that is opposed to the driving roller is rotatably supported at one end and the other end is connected to the urging means, and the position between them is a fulcrum portion. In the sheet conveying apparatus having a roller support that is supported so as to be swingable, a plurality of the fulcrum portions are provided in the length direction of the roller support, and the sandwiching pressure is applied to the sheet that passes between the driving roller and the driven roller. The lever ratio of the roller support body can be changed by changing the position of the fulcrum portion so that is substantially constant.
According to the first aspect of the present invention, it is possible to change and adjust the pressing force only by changing the lever ratio of the support body without exchanging the driven roller or the biasing means.

According to a second aspect of the present invention, in the first aspect, the fulcrum portion is formed with a plurality of concave grooves formed in the support, and a fulcrum portion that engages the concave grooves so as to be detachable from each other. A plurality of fulcrum pins.
According to this aspect, in addition to the operational effects of the first aspect, the present invention can be realized with a simple structure by a specific configuration that engages the fulcrum pin facing the concave groove at the position where the lever ratio is desired to be changed.

According to a third aspect of the present invention, in the first or second aspect, the concave groove and the fulcrum pin are provided at two positions corresponding to the lever ratio changing position, one of which is fixed and the other is movable. The movable fulcrum pin is detachably engaged with the opposing concave groove by an external operation, and in the engaged state, the fixed fulcrum pin is separated from the opposing concave groove. It is characterized by.
According to this aspect, in addition to the operational effects of the first or second aspect, the fixed fulcrum pin is reliably separated from the concave groove when the movable fulcrum pin is engaged. Can be reliably switched.

According to a fourth aspect of the present invention, in the third aspect, the movable fulcrum pin has a cam shape in which the movable fulcrum pin is connected to an operation rotary shaft, and the concave groove that engages with the cam has a circular arc shape along the cam lead surface. It is characterized by having made.
According to this aspect, in addition to the operation and effect of the third aspect, the switching work can be performed by a simple operation from the outside.

According to a fifth aspect of the present invention, in the recording apparatus including the sheet conveying device according to any one of the first to fourth aspects, a counting unit that detects the passage of the sheet and counts it, And a warning means for instructing switching of the fulcrum position when the cumulative number counted by the counting means reaches a predetermined number.
According to this aspect, the change timing of the lever ratio of the recording apparatus can be determined simply by the cumulative number of passing sheets. In other words, since it is only necessary to determine the characteristic change timing of the driven roller based on the number of processed sheets and thereby set the change timing in advance, the conventional detection means such as a pressure sensor is not necessary, and the mechanical life is reduced. By preventing the occurrence of problems caused by the driven roller in the latter period and switching the fulcrum position based on the alarm, the recording apparatus can be used continuously without causing problems caused by the driven roller.

A sixth aspect of the present invention is characterized in that, in the fifth aspect, there is provided switching means for performing a fulcrum position switching operation when the cumulative number counted by the counting means reaches a predetermined number. Is.
According to this aspect, in addition to the effects of the fifth aspect, the fulcrum position is automatically changed when the change time is reached, so that there is no need to bother with every fulcrum change.

The best mode of the present invention will be described below with reference to the drawings.
FIG. 1 is an overall perspective view of the internal structure of the ink jet recording apparatus according to the present invention excluding an exterior housing, as viewed from the paper discharge end side, and FIG. 2 is a partial side view of a paper feed mechanism portion. In the figure, a recording apparatus (hereinafter abbreviated as “apparatus”) 10 includes an apparatus main body (hereinafter abbreviated as “main body”) 14 assembled on a mount base 12.

  The main body 14 includes a pair of front and rear main frames 16 and 18 disposed in the front and rear in the main scanning direction which is a horizontal direction, and a pair of side frames 20 and 22 disposed on both sides in the sub scanning direction which is the front and rear direction. A platen 24 that supports a sheet as a recording medium is fixedly disposed at the bottom of the platen 24, and is disposed at one end in the main scanning direction via a carriage guide 26a. A carriage 26 that is guided so as to be reciprocally movable toward the other end side is disposed.

  A recording head 28 is mounted below the carriage 26, and the platen 24, the carriage 26, the recording head 28, and the like constitute a recording unit.

  The sheet fed onto the platen 24 from the rear sheet feeding side is recorded by the reciprocating movement of the carriage 26 in the main scanning direction, and the lower sheet feeding driving roller, which will be described later, rotates in synchronization therewith. 30 (shown only in FIG. 2) and the paper is fed in the sub-scanning direction while being sandwiched between the driven rollers 32, and passes through a sheet discharge unit (not shown) disposed in front of the platen 24 and the lower part of the front main frame 16. The paper is discharged onto a paper discharge tray (not shown) on the paper discharge end side of the mount base 12.

  The paper feeding mechanism for feeding and discharging is collectively driven via a timing pulley and a timing belt by a paper feeding driving motor 34 fixed inside the front portion of one side frame 20.

  That is, a small-diameter timing pulley 34 a that is axially coupled to the drive shaft of the drive motor 34 protrudes from the outer portion of the side frame 20, and a large-diameter that is connected to the drive roller 30 at the rearmost portion of the side frame 20. The paper feed pulley 36 protrudes, and a large-diameter paper discharge pulley 38 connected to the front end of the paper discharge unit protrudes at an intermediate position of the side frame 20, and a timing belt 40 is interposed between these pulleys 34, 36, 38. The paper feeding operation is performed according to the driving of the motor 34.

  In FIG. 2, a sheet as a recording medium fed from a sheet feeding tray (not shown) is delivered to a lower sheet guide 42 and fed toward a roller pair including the driving roller 30 and a driven roller 32. The paper is sandwiched between the rollers 30 and 32 and sent toward the recording execution area in the main body 14.

  Both ends of the driving roller 30 are rotatably supported between the side frames 20 and 22 and are driven to rotate by a paper feed pulley 36 disposed outside the one side frame 20.

  On the other hand, the driven roller 32 is rotatably supported at the tip of the upper sheet guide 44 that is a roller support. The front end side of the upper paper guide 44 protrudes into the main body 14 through the lower opening of the rear main frame 18, and the rear side is connected to a tension coil spring 46 whose upper end is connected to the rear surface of the main frame 18.

  In addition, arc-shaped concave grooves 48a and 48b constituting two fulcrum portions are formed in front and rear of the middle portion of the upper paper guide 44, respectively. Among these, the front side concave groove 48a is engaged with a fixed fulcrum pin 50 protruding from the lower edge of the plate 50a fixed to the back surface of the main frame 18, and the rear side concave groove 48b has a cam shape. The rotary fulcrum pin 52 is detachably engaged, and the rear-side concave groove 48b is an arc surface along the cam lead shape of the rotary fulcrum pin 52. A rotating shaft 52a in which the movable fulcrum pin 52 is integrated is pivotally supported by the side frames 20 and 22 so that both ends thereof can be rotated.

  In the above configuration, at the initial stage of use of the device 10, as shown in FIG. 3A, the rotary fulcrum pin 52 is engaged with the opposed rear side concave groove 48b. In this state, the fixed fulcrum pin 50 is engaged. Is spaced apart from the front concave groove 48a. Therefore, with the position of the fulcrum pin 52 as an effective fulcrum portion, the driven roller 32 is pressed against the drive roller 30 by the pressing force based on the spring pressure of the spring 46 and the lever ratio corresponding to the contact position.

When the pressing force applied to the driven roller 32 is F1, the tensile force of the spring 46 is W, and the lever lengths before and after the fulcrum pin 52 are L1 and L2, the pressing force acting on the driven roller 32 is set. The pressure F1 is
F1 = W · L2 / L1
It becomes.

Next, as shown in FIG. 3 (b), when the fulcrum pin 52 is removed from the rear side concave groove 48b by rotating the shaft 52a by 180 °, the fixed side fulcrum pin 50 is now moved to the front side concave groove. 48a is engaged, and this position becomes an effective fulcrum portion. If the front and rear lever ratios in this case are L1 ′ and L2 ′, the pressing force F2 acting on the driven roller 32 after the change is
F2 = W · L2 '/ L1'
It becomes.

And (L2 / L1) <(L2 ′ / L1 ′)
Since this is apparent from the geometric shape, the pressing force before and after the change clearly becomes F2> F1 by this changing operation, and the pressing force increases.

  1 and 2 again, the upper portion of the main body 14 is covered with an exterior panel (not shown), and a display unit, operation buttons, and switches (not shown) are arranged on the front side of the exterior panel. Inside, electronic devices connected to these are built-in.

  Among electronic devices, FIG. 4A shows an electrical configuration for monitoring the pressing force change timing between the driving roller 30 and the driven roller 32. Reference numeral 56 is a counter for detecting addition of paper, reference numeral 58 is the display section, and reference numeral 60 is a switch for detecting switching of the fulcrum pin 52. These are connected to the CPU 62 which is also used for command / execution of other control functions. The CPU 62 executes the following control as shown in FIG. 4B based on the program contents built in the ROM 64 and the contents temporarily stored in the RAM 66.

  First, every time a sheet passes between the rollers 30 and 32, the counter 56 detects it, and the CPU 62 sequentially accumulates the detected values as the number of sheets (step ST1). Then, when the integrated number reaches the set value, the fact is displayed on the display unit 58 to prompt lever ratio switching (step ST2).

  There are various display methods, such as displaying characters on a liquid crystal display or the like, and blinking an alarm lamp. In addition to this, a sound guide or the like can be used in combination according to the sound of the buzzer or the program contents.

  Based on this alarm display, the user rotates the shaft of the fulcrum pin 52 by 180 °, that is, if the answer is YES in step ST4, the process is terminated. When the switching operation is not performed without noticing, the alarm display is continued, the power is turned off, and the same alarm can be repeated at the next power-up.

  As described above, the setting time of the above switching is set as a guide around passing about 50,000 sheets while the life number of the entire apparatus 10 is acceptable up to about 100,000 sheets as described above. Of course, it should be determined in consideration of safety and safety factors.

  After the change of the fulcrum position, it is possible to prevent problems caused by a decrease in the pressing force of the driven roller 32 such as paper jam and printing failure, and after that, good paper feeding operation is continued until the machine life is reached. It becomes.

  FIG. 5 shows a specific configuration example for the above switching. A switching knob 52b is provided outside the side frame 20 at one end of the shaft 52a, and the knob 52b is moved by the user's hand. The fulcrum pin 52 is separated from the rear-side concave groove 48b by turning 180 ° with reference to an alignment mark (not shown) displayed in the vicinity thereof, and the fulcrum pin is moved to the fixed fulcrum pin 50 side. It is shifted. As an example of the detection switch 60 for confirming this operation, there is a micro switch attached to the plate 50a as shown in the figure, and the detector 60a is a fulcrum pin at the 180 ° rotation position of the shaft 52a from the state shown in the figure. 52 is in contact with the cam lead surface and generates a detection signal.

  In the above embodiment, the switching operation is manually performed based on the warning display. However, an automatic switching unit can be added instead of the knob or the like, and of course, it can be performed by a motor, an electromagnetic solenoid, or the like. It is.

  Further, in the embodiment, only one switching of the apparatus life is performed, but it is needless to say that the fulcrum position change and the lever ratio change can be performed a plurality of times by providing a plurality of positions serving as fulcrum portions.

1 is an overall perspective view showing an internal structure of a recording apparatus according to the present invention as viewed from the front side. The fragmentary sectional view which shows the paper feed mechanism part arrange | positioned at the rear part main frame rear part. (A), (b) is an expanded sectional view in the III section in a circle of FIG. FIG. 4A is a block diagram showing an electrical configuration for monitoring a timing for changing a pressing force between rollers in the recording apparatus, and FIG. 4B is a flowchart showing an execution procedure thereof. The fragmentary perspective view which shows an example of the specific structure for switching.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Recording device, 12 Mount base, 14 Apparatus main body, 16, 18 Main frame, 20, 22 Side frame, 24 Platen, 26 Carriage, 26a Carriage guide, 28 Print head, 30 Paper feed drive roller, 32 Drive roller, 34 paper feed drive motor, 34a, 36, 38 timing pulley, 40 timing belt, 42 rear paper guide, 44 upper paper guide (roller support), 46 tension coil spring (biasing means), 48a, 484b concave groove, 50a Plate, 50 Fixed fulcrum pin, 52 Rotating fulcrum pin, 52a Rotating shaft, 52b Knob, 54 Exterior panel, 56 Counter, 58 Display unit, 60 Detection switch, 62 CPU, 64 ROM, 66 RAM

Claims (6)

A sheet transport having a roller support that rotatably supports a driven roller opposite to the driving roller at one end, and is connected to an urging means at the other end so as to be swingable with a position therebetween as a fulcrum. A device,
A plurality of the fulcrum portions are provided in the length direction of the roller support, and the roller support is changed by changing the position of the fulcrum so that the holding pressure on the sheet passing between the driving roller and the driven roller is substantially constant. A sheet conveying apparatus characterized in that the lever ratio can be changed.   2. The sheet conveying apparatus according to claim 1, wherein the fulcrum part is formed with a plurality of concave grooves formed on the support body, and a plurality of fulcrum pins for forming a fulcrum part that are detachably engaged with each other while facing the concave grooves. A sheet conveying apparatus characterized by the above.   3. The sheet conveying apparatus according to claim 1, wherein the concave groove and the fulcrum pin are provided at two locations corresponding to the lever ratio changing position, one of which is fixed and the other is movable. The seat is characterized in that the fulcrum pin is detachably engaged with the opposing concave groove by an external operation, and in the engaged state, the fixed fulcrum pin is separated from the opposing concave groove. Conveying device.   4. The sheet conveying device according to claim 1, wherein the fulcrum pin has a cam shape in which the operation pin is connected to a rotating shaft for operation, and a concave groove that engages with the cam has a circular arc shape along the cam lead surface. 5. A sheet conveying apparatus characterized by comprising:   5. A recording apparatus comprising the sheet conveying apparatus according to claim 1, wherein the recording unit detects the passage of the sheet and counts the sheet, and the accumulated number of sheets counted by the counting unit. Comprises a warning means for instructing switching of the fulcrum position when the predetermined number of sheets is reached.   6. The recording apparatus according to claim 5, further comprising switching means for performing a fulcrum position switching operation when the cumulative number counted by the counting means reaches a predetermined number.

Images