JP2000191194A - Machine glazed paper feeder for picture image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a machine glazed paper feeder capable of stably and favourably feed machine glazed paper without sagging. SOLUTION: This machine glazed paper feeder has a paper presser mechanism supported free to move in a direction to cross a forwarding route of machine glazed paper 15 drawn from a roll 18 as a sagging preventive means to prevent occurrence of sagging of the machine glazed paper to be fed or to absorb it afterward. This paper presser mechanism has a roller 33 as a paper pressing part to lean against the machine glazed paper on the forwarding route by dead weight. A device to brake a spool 16 installed on the roll 18 by a short brake, an electromagnetic clutch, etc., of a motor also does as another sagging preventive means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus using roll paper.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus using roll paper as a recording medium, the roll paper is transported (drawn) by a paper transport roller on a platen. And so on, so that it is attracted onto the platen.

[0003]

However, this configuration covers unevenness of the paper suction force by the suction fan (varies depending on the type and size of the paper) and the floating of the paper due to the curl of the paper (particularly when roll paper is used). Can be difficult to do.

In addition, when the roll paper is fed, the amount of roll paper pulled out is not constant due to the inertia of the roll, and the back tension due to the roll paper is not constant.
The load condition for the paper conveyance changes, and as a result, there is a possibility that problems such as unevenness between printing bands due to poor paper feeding and paper conveyance failure may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of such a background, and an object of the present invention is to provide a roll paper feeder capable of feeding roll paper stably and without any slack.

[0006]

A roll paper feeder for an image forming apparatus according to the present invention is a roll paper feeder in an image forming apparatus for forming an image on roll paper. It is characterized by having a paper feeding means for feeding paper to the forming position, and a slack preventing means for preventing the occurrence of the slack of the roll paper fed by the paper feeding means or absorbing it later.

[0007] The slack preventing means has, for example, a paper pressing mechanism movably supported in a direction crossing the roll paper traveling path, and the paper pressing mechanism leans against the roll paper on the traveling path by its own weight. It has a paper holder that hangs.

As an example of the paper holding mechanism, there is provided a paper supporting portion for supporting the roll paper in the width direction at a position between the roll and the platen, and the paper pressing portion swings around the paper supporting portion as a fulcrum. . In this case, it is preferable that the paper pressing portion has a rotating member that comes into contact with the roll paper so as not to damage the roll paper surface.

The roll paper is held by a spool, and when the spool rotates in accordance with the drawing of the roll paper, the slack preventing means can be constituted by brake means for applying a brake to the rotation of the spool. .

The brake means includes a motor having a shaft to which the rotation of the spool is transmitted, and switch means for short-circuiting a pair of drive terminals of the motor. Alternatively, the brake means is constituted by an electromagnetic clutch for giving resistance to the rotation of the spool, and a control circuit for controlling the driving of the electromagnetic clutch. In either case, it is possible to control the ON / OFF of the electromagnetic clutch or the switch in accordance with the means for detecting the rotational speed of the spool and the detected rotational speed.

Another form of the brake means is that at least one piece which rotates simultaneously by the rotation of the spool and moves in the direction of rotation by centrifugal force, and a brake pad fixed to this piece, rotates. A frame member fixed in the apparatus, which comes into contact when the piece moves in the radial direction.

Further, when the roll paper is held by a spool, and the spool rotates in accordance with the drawing of the roll paper, the slack preventing means rotates the spool to wind up the generated slack of the roll paper. It can also be configured with a motor that drives the motor.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a roll paper feeder of the present invention will be described in detail with reference to the drawings, taking an ink jet recording apparatus as an example.

1 and 2 are a front perspective view and a rear perspective view, respectively, of an ink jet recording apparatus according to the present embodiment.

FIG. 1 shows a state in which the cover 17 is opened so that the internal carriage 14 and the like can be seen. The recording head 11 that ejects ink is mounted on the carriage 14. The carriage 14 moves along a guide shaft 13 via a slide bearing (not shown) under the control of a recording control unit by a motor and a belt (neither is shown), and moves the recording head 11 to the guide shaft. 13 can be reciprocated in parallel. For example, two parallel guide shafts 13 are installed above the platen 12 in parallel with the platen 12.

As can be seen from FIG. 2, the roll 18 around which the roll paper 15 is wound is set on a spool 16 and set on a roll holder behind the apparatus. From here, the roll paper 15 is pulled out to the front side through the inside of the apparatus. When the roll 16 is pulled out, the spool 16 is
Rotates with. The roll paper 15 is recorded on the platen 12 by the recording head 11, and is driven and conveyed by a grid roller and a pinch roller (21 and 22 in FIG. 3) to move on the platen 12. That is,
After an image of the nozzle width is formed by one scan of the carriage 14, the roll paper 15 is transported by the nozzle width. By repeating this, the entire image is formed. In the figure, reference numeral 19 denotes an operation panel for performing key input by the user and display to the user.

As recording paper, in addition to roll paper,
Although cut paper can also be used, the present invention relates to the supply of roll paper, and hence only roll paper will be described below.

At the time of printing, the roll paper 15 is conveyed by the above-mentioned grid roller and pinch roller. At this time, the roll 18 and the spool 16 are rotated by the conveying force, and the inertia of the roll 18 and the spool 16 rotates more than the "nozzle width". May be done. As a result, floating of the roll paper 15 on the platen (FIG. 3) and sagging of the paper (FIG. 4) occur, which fluctuate the conveying force,
As a result, the printing quality was reduced.

Therefore, in the present invention, the variation of the conveying force,
The following various mechanisms and controls are provided to suppress paper floating, paper slack, and the like.

Before describing each embodiment, the time change of the transport state of roll paper will be described with reference to FIG. In the figure, the horizontal axis represents time, and the vertical axis represents three elements of the transport motor transport speed (•), roll feed speed (×), and brake amount (ブ レ ー キ). Section A indicates the acceleration period of the transport motor, section B indicates the constant speed period of the transport motor, and section C indicates the deceleration period of the transport motor. In the sections A and B, the transport speed is equal to the roll paper sending speed, so that the roll paper does not sag. However, in the section C, the roll tries to keep the feeding speed due to inertia while the transport motor starts the deceleration operation. For this reason, the speed at which the roll paper is sent out exceeds the transport speed, and this speed difference causes the roll paper to sag. To eliminate this slack before or afterwards,
Provide a slack prevention mechanism. The slack prevention mechanism includes a paper holding mechanism, a brake mechanism, and the like, which will be described later. The paper holding mechanism gives tension to the generated slack. The brake mechanism eliminates or reduces the speed difference. That is, by applying the brake by the brake mechanism, the roll feeding speed matches the transport speed, and it is possible to prevent the occurrence of the slack of the roll.

<First Embodiment> FIG. 5 shows the configuration of the present embodiment. The paper holding mechanism includes a paper holding mechanism movably supported in a direction traversing the traveling path of the roll paper drawn from the roll, and the paper holding mechanism has a paper holding section that leans against the roll paper on the traveling path by its own weight. .

More specifically, the swing roller mechanism includes a roller (roller) 3 rotatably supported by a fixed shaft 32.
5, two parallel link members 34 swingably supported by the fixed shaft 32, and rollers 33 (paper pressing portions) rotatably supported between the free ends of both link members 34. Having. The roll paper 15 is set so as to be supplied from above the roller 35 to the platen 12 through below the roller 33. Thus, the roller 33 functions to always apply tension to the roll paper 15 by its own weight. That is, even when the remaining amount of the roll paper 15 is large or small, the roll paper 15 can be pressed between the roller 18 and the platen 12 with a certain force or more.
As a result, it is possible to prevent the paper from floating or sagging and to perform stable and favorable paper feeding.

The rollers 33 and 35 are not essential components, but by providing them (particularly the rollers 33), smooth paper feed can be realized without damaging the roll paper surface.

<Embodiment 2> FIG. 6 shows the configuration of the present embodiment.

In this embodiment, the DC motor 41 is set on the spool 16 of the roll paper 15. That is, the gear 44 attached to the shaft of the DC motor 41 meshes with the gear 45 attached to the shaft 46 connected to the spool 16. An encoder plate 42 is attached to the shaft 46, and the rotation is monitored by a sensor 43.

As shown in the circuit diagram of FIG.
1 are connected to a switch 52 at both ends.
By turning on the switch 52 by 1, a so-called “motor short brake” is formed for the rotation of the spool 16. With this configuration, the spool 1
6, a certain load or more is imposed on the spool 6, and an extra rotation of the spool 16 due to inertia can be suppressed.
It is possible to prevent the paper from sagging.

Further, the encoder plate 42 and the sensor 43
, The rotation speed of the spool 16 is detected. The CPU 51 detects a signal (encoder pulse) from the sensor 43, and turns on the switch 52 when the spool 16 has exceeded a certain number of rotations to generate a braking force. That is, when the paper is started to be conveyed, the brake amount is "0" (the switch 52 is OFF), and the short brake is activated at a predetermined rotation speed or more (immediately before the paper sags due to inertia) (the switch 52 is ON). .

FIG. 8 is a diagram showing the relationship between the driving state of the motor and the roll paper feed amount in the circuit of FIG.
At time t0, the paper transport motor is turned on, thereby starting to feed out the roll paper. At time t1, the rotation speed of the spool 16 reaches a predetermined value, and at this time, the switch 52 is turned on for a predetermined time (until time t2). This allows the spool 16
A brake is applied to the rotation of the paper, and a proper amount of paper can be conveyed without sagging of the paper.

With this configuration, it is possible to apply an optimal brake to the inertia of the roll 18, to minimize the slack of the roll paper 15, and to perform stable and good paper feeding.

In the present embodiment, the encoder 42
A configuration is also conceivable in which the switch 52 is turned on immediately before the paper transport motor is turned off without using the sensor 43.

<Embodiment 3> FIG. 9 shows the configuration of the present embodiment. In the embodiment of FIG. 6, a short brake of the motor is used as a brake for the rotation of the spool 16, but in this embodiment, an electromagnetic clutch 71 is used. That is, the electromagnetic clutch 71 is set to the spool 16 of the roll paper 15 via the gears 46 and 47. By controlling the ON / OFF of the electromagnetic clutch 71, it is possible to apply a brake to the rotation of the spool 16, thereby suppressing the excessive rotation of the spool 16 due to inertia and preventing the paper from sagging. Becomes possible.

However, when only the ON / OFF control is performed, the brake amount when the electromagnetic clutch is ON is constant, and it is conceivable that an excessive brake is applied or the brake amount becomes insufficient. Therefore, an encoder plate 42 and a sensor 43 are provided on the extension of the spool 16 to detect the rotation speed of the spool 16. CPU by signal from sensor 43
Reference numeral 51 can detect the number of rotations. The voltage applied to the electromagnetic clutch 71 is adjusted by the regulator IC 81 according to the rotation speed. Thereby, the electromagnetic clutch 7
1 can adjust the amount of braking.

FIG. 11 shows an operation timing chart of the embodiment of FIG. At time t10, the paper transport motor is turned on,
After that, when the CPU 51 detects that the spool 16 has reached the rotation speed at which unnecessary inertia starts to be applied at time t11 by the input from the sensor 43, the electromagnetic clutch 71 is turned on. At this time, in order to apply a small voltage (because the paper is still being conveyed), the CPU 51
81 (FIG. 10A) is given a predetermined value as the voltage Vref. The regulator IC 81 has an internal configuration as shown in FIG. 10B and has characteristics as shown in FIG. That is, by changing Vref, the output voltage of the regulator IC 81 changes. The relationship between the output voltage and the braking amount is almost proportional. At the time (t12) when the conveyance of the paper is completed in the sequence (t12), the voltage applied to the electromagnetic clutch 71 is maximized (here, 24
V), a predetermined voltage is applied to the regulator IC 81.

With this configuration, it is possible to apply an optimum brake to the inertia of the roll 18, to minimize the slack of the roll paper 15, and to perform stable and good paper feeding.

<Fourth Embodiment> FIG. 12 shows the structure of a brake mechanism according to a fourth embodiment. In the present embodiment,
A brake mechanism is provided for the spool 16 of the roll paper 15, which automatically works by rotation of the spool 16. The internal structure of this brake mechanism has the following configuration.

A plurality of (here, four) shafts 101 are radially attached to the shaft 46 connected to the spool 16, and a top 102 is slidably passed through each of the shafts 101. Top 10
A pad 103 is fixed to the tip of the second. On the other hand, a fixed (non-rotating) frame 105 is provided in the apparatus, and a pad 106 is attached to the inside of the frame 105. There is some gap between the tip of the shaft 101 and the inner surface of the pad 106.

Each shaft 101 rotates following the rotation of the spool 16, and the top 102 moves toward the frame 105 by the centrifugal force generated by the rotation of the shaft 101. When the centrifugal force is applied to a certain degree or more (when the number of rotations is equal to or more than a certain number of rotations), the top 102 comes into contact with the frame 105, and the friction caused by this contact applies a brake to the rotation of the spool 16. When the spool 16 is not rotating, the spring 1
The frame 104 is drawn to the shaft 46 side by 04 and does not contact the frame 105.

FIG. 14 shows the change over time of the roll paper feed amount in the present embodiment. With this configuration, it is possible to apply a brake to the inertia of the roll 18, to minimize the slack of the roll paper 15, and to perform stable and good paper feeding.

<Fifth Embodiment> FIG. 15 shows the structure of a slack preventing mechanism according to a fifth embodiment. In this embodiment, a winding motor 131 that rotates in the direction in which the roll paper 15 is wound is provided. That is, the take-up motor 131 drives the spool 16 via the gears 44 and 45.
To rotate. The take-up force is smaller than the paper conveyance force and the paper holding force by the grid roller and the pinch roller. In other words, the force of the take-up motor 131 is sufficiently small with respect to the paper conveyance force, so that the paper once conveyed is not pulled back except for absorbing the slack.

As shown in FIG. 16, the motor 131
It is controlled by the PU 51 via the motor driver 141.

FIG. 17 shows the relationship between the driving state of the paper conveying motor and the winding motor 131 and the roll paper feed amount in this embodiment. When paper feeding is started at time t20, the paper transport motor is turned on. At this time, the winding motor 131 remains OFF. Time point t2
After the rotation of the transport motor is completed in 1 (the transport of the paper is completed), the winding motor 131 is turned on. The winding motor 131 is turned off after being rotated for a time (until time t22) sufficient to eliminate the slack of the paper.

With this configuration, the roll paper 15 can be wound up, slack of the roll paper 15 due to inertia can be eliminated, and stable and satisfactory paper feeding can be performed.

[0043]

According to the present invention, stable and good roll paper feeding without sagging can be performed, so that print quality can be improved.

[0044]

[Brief description of the drawings]

FIG. 1 is a front perspective view of an ink jet recording apparatus to which the present invention is applied.

2 is a perspective view of the back of the device of FIG. 1;

FIG. 3 is an explanatory diagram of a state in which roll paper floats to be solved by the present invention.

FIG. 4 is an explanatory diagram of a state in which the roll paper has become slack to be solved by the present invention.

FIG. 5 is a diagram schematically showing a configuration of the first embodiment of the present invention.

FIG. 6 is a diagram schematically illustrating a configuration of a second embodiment of the present invention.

FIG. 7 is a circuit block diagram of the configuration of FIG. 6;

FIG. 8 is an operation timing chart of the configuration of FIG. 6;

FIG. 9 is a diagram schematically showing a configuration of a third embodiment of the present invention.

FIG. 10 is a circuit block diagram of the configuration of FIG. 9;

FIG. 11 is an operation timing chart of the configuration of FIG. 9;

FIG. 12 is a diagram schematically showing a configuration of a fourth embodiment of the present invention.

FIG. 13 is a diagram showing a configuration of a main part of the configuration of FIG. 12;

FIG. 14 is an operation timing chart of the configuration of FIG. 12;

FIG. 15 is a diagram schematically showing a configuration of a fifth embodiment of the present invention.

FIG. 16 is a diagram showing a configuration of a main part of the configuration of FIG. 15;

FIG. 17 is an operation timing chart of the configuration of FIG. 15;

FIG. 18 is a graph for explaining a change over time in a transport state of roll paper.

[Explanation of symbols]

11 ... Head, 12 ... Platen, 13 ... Guide shaft, 14 ... Carriage, 15 ... Roll paper, 16 ... Spool, 18 ... Roll, 19 ... Operation panel, 21 ... Grid roller, 22 ... Pinch roller, 31 ... Shaft (Roll) Paper holding side), 32: Shaft (fulcrum side), 33: Roller (roll paper holding side), 34: Link member, 35: Roller (fulcrum side), 41: DC motor, 42: Encoder plate,
43 ... sensor, 51 ... CPU, 52 ... switch, 71 ...
Electromagnetic clutch, 81: Regulator IC, 101: Shaft, 102: Frame, 103: Pad (of frame), 10
4 Spring, 105 Pad (of frame), 106 Frame, 131 Winding motor, 141 Driver IC.

Claims (11)

[Claims] 1. A roll paper feeder in an image forming apparatus for forming an image on roll paper, comprising: paper feed means for feeding roll paper drawn from a roll to an image forming position; A roll paper feeder for an image forming apparatus, comprising: a slack preventing means for preventing the occurrence of slack of a roll paper to be printed or absorbing it later. The slack preventing means has a paper holding mechanism movably supported in a direction crossing the traveling path of the roll paper, and the paper holding mechanism leans against the roll paper on the traveling path by its own weight. 2. The roll paper feeder for an image forming apparatus according to claim 1, further comprising a paper holding portion that hangs. 3. The paper press mechanism has a paper support section for supporting the roll paper in the width direction at a position between the roll and the platen, and the paper press section swings around the paper support section as a fulcrum. The roll paper feeding device for an image forming apparatus according to claim 2, wherein: 4. A roll paper feeder for an image forming apparatus according to claim 3, wherein said paper presser has a rotating member which comes into contact with the roll paper. 5. The roll paper is held by a spool, the spool rotates in accordance with the roll paper being pulled out, and the slack preventing means has a brake means for applying a brake to the rotation of the spool. The roll paper feeder for an image forming apparatus according to claim 1. 6. The brake device according to claim 1, wherein said brake means comprises a motor having a shaft to which rotation of said spool is transmitted, and switch means for short-circuiting a pair of drive terminals of said motor. 6. A roll paper feeder for an image forming apparatus according to claim 5. 7. A means for detecting a rotation speed of the spool, and an operation of the switch means in accordance with the detected rotation speed.
The roll paper feeding device for an image forming apparatus according to claim 6, wherein N / OFF is controlled. 8. An image forming apparatus according to claim 5, wherein said brake means comprises an electromagnetic clutch for giving a resistance to rotation of said spool, and a control circuit for controlling driving of said electromagnetic clutch. Roll paper feeder. 9. A roll paper feeder for an image forming apparatus according to claim 8, wherein said means for detecting a rotational speed of said spool and a resistance force by said electromagnetic clutch are controlled in accordance with the detected rotational speed. Paper equipment. 10. The brake means, wherein the brake means rotates simultaneously with the rotation of the spool, and at least one frame which moves in a radial direction of rotation by centrifugal force, a brake pad fixed to the frame, and the frame which rotates. 6. The roll paper feeder for an image forming apparatus according to claim 5, further comprising: a frame member fixed in the apparatus, which comes into contact when the paper moves in a radial direction. 11. The roll paper is held by a spool, the spool rotates in accordance with the drawing of the roll paper, and the slack preventing means rotates a motor for rotating the spool to wind up the generated slack of the roll paper. 2. The roll paper feeding device for an image forming apparatus according to claim 1, further comprising: