JP2000335758A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a printer in which the paper feeding roller stands by away from the paper surface for enhancing paper-feeding accuracy by three- dimensionalizing the arrangement of the printing part or the like so that the distance between the paper-feeding roller and the feed-roller can be prolonged. SOLUTION: A paper-feeding roller is divided into two paper-feeding rollers 1, 2 and the paper on the paper-feeding cassette 8 is carried up to the paper- feeding roller 2 by the paper-feeding roller 1, and the paper-feeling roller 2 carries the paper sheet carried from the paper-feeding roller 1 up to a feed-roller 5. After carriage, the paper-feeding roller 1 stops rotation and stands by until the subsequent paper-feeding time in the stand-by position apart above from the paper surface, while the paper-feeding roller 2 stops after carriage and becomes a free condition. Paper-feeding roller driving parts 3, 4 are made up of a gear group for driving the paper-feeding rollers 1, 2 carrying out the above action. The more the rotating speed of the paper-feeding roller 2 becomes at the time of paper feeding, the longer the distance between the paper-feeding roller and the feed-roller can be taken.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer, and more particularly to a paper feed roller in which rotation of a paper feed roller is stopped except during a paper feeding operation, and at the same time, the paper feed roller is moved to a position above the paper and stands by to improve the accuracy of paper conveyance. The present invention relates to a printer using a paper roller driving device.

[0002]

2. Description of the Related Art In various printers such as a thermal transfer printer and an ink jet printer which are generally used as output devices such as a computer, a word processor and a facsimile, a separating mechanism on which a plurality of sheets are set when desired recording is performed. Is mounted on the printer body, and the paper stored in the paper cassette is brought into contact with a paper feed roller that is driven to rotate. The paper is fed toward. The paper feed roller is formed so as to be able to rotate the driving force of a drive motor by a paper feed roller driving device constituted by a gear group.

In a printer of this type, as a method of bringing a paper into contact with a paper feed roller that rotates and drives the paper in order to improve paper conveyance accuracy in particular, the paper feed roller is held movably up and down, Is located at the top, falls while rotating at the time of paper feeding, and comes into contact with the paper stored in the paper feeding cassette so as to send out the uppermost one so as not to hinder the subsequent conveyance of the paper. There is a printer that moves upward and is on standby.

FIGS. 5 and 6 show an example of this type of printer.
Shown in FIG. 5 is a configuration diagram showing a structure of a paper feeding portion related to the paper feeding operation, and FIG. 6 is a side view of the paper feeding roller driving portion showing an operation process of the paper feeding roller driving portion in FIG.

In FIG. 5, a paper feed roller 51 having a vertical movement mechanism for transporting sheets 56 stored in a paper feed cassette 55 one by one to a feed roller 53, and a rotational driving force of a drive motor (not shown). And a paper feed roller driving unit 52 constituted by a gear group for rotating the paper feed roller up and down and rotating, and receiving the paper 56 rotated by the drive motor and conveyed by the paper feed roller 51 and printing it. 5
The paper feed unit is constituted by the feed roller 53 for feeding the paper to the feed roller 4.

Next, an outline of the operation will be described. A drive motor (not shown) is activated by receiving a start signal of a printing operation of the printer from a control unit (not shown). The paper feed roller 51 is at a position above the paper 56 in the paper feed cassette 55 during standby, and rotates down by a drive motor to descend on the paper 56 and makes a slight rotation, and then from the surface of the paper 56 The robot returns to the upper position and stops rotating. The paper 56 is fed forward by this distance by the one-turn weak rotation operation of the paper feed roller 51.

[0007] The feed roller 53 has
The paper 56 is provided at a distance capable of receiving the paper 56 to be fed with a low rotation, and is rotated in the direction opposite to the paper transport direction at this time by the drive motor. This is to ensure that the leading edge of the conveyed sheet is pressed against the roller surface, and the feed roller 53 can surely capture the conveyed sheet. At this point, the control unit detects the paper position and issues a control signal to reverse the rotation direction of the drive motor. As a result, the rotation direction of the feed roller 53 is changed to the paper transport direction and the paper is sent to the printing unit 54. During feeding of the sheet by the feed roller 53, that is, during printing, the sheet feeding roller 51 does not contact the sheet surface, so that it does not hinder printing.

Next, referring to FIG.
Will be described. FIG. 6A shows a state at the start of sheet feeding when the drive motor starts rotating. The paper feed roller driving unit 51 is provided with a main gear 521 to which the rotational driving force of the driving motor is transmitted, and is always meshed with the main gear 521 and is supported by a swinging plate. Other than the above, a swing gear 522 that meshes with the sub gear 524 ′, a paper feed roller drive gear 526 that rotationally drives the paper feed roller 51, and is always meshed with the paper feed roller drive gear 526 and is formed coaxially with the sub gear 524 ′. A transmission gear 524, an intermediate gear 523 that always meshes with the transmission gear 524, and a cam 52 formed coaxially with the paper feed roller driving gear 526 to move the paper feed roller 51 up and down.
And 5.

Next, the operation will be described. In FIG. 6A, when the main gear 521 starts rotating due to the rotation of the drive motor, the swing gear 522 swings, meshes with the intermediate gear 523, and the feed roller drive gear 523 rotates via the transmission gear 524. When the hook 525 is disengaged from the stopper 527, the paper feed roller 51 moves downward, contacts the paper surface of the paper feed cassette 53, and sends the paper forward. FIG. 6B shows a state at the time of paper feeding at this time.

When the paper feed roller 51 rotates nearly one rotation, the cam 525 slides on the stopper 527 and frequently moves it upward to stop the paper feed operation. However, since the paper sent at this time reaches the feed roller 53, the drive motor rotates in the reverse direction. As a result, the rotation direction of the main gear 521 is reversed, and the swing gear 522 swings and meshes with the sub gear 524 '. Is rotated, the rotation is not transmitted to the toothed portion provided on the sub gear 524 ', and the paper feed roller 51 stops rotating. FIG. 2 (3) shows the state when the reverse rotation is stopped.
This state is a standby state, and the next sheet feeding is performed as shown in FIG.
And the same operation is repeated.

[0011]

As described above, in the conventional example, the installation distance between the paper feed roller and the feed roller is limited to within a distance at which the paper feed roller rotates slightly less than one turn to feed the paper. . In order to allow the distance between the paper feed roller and the feed roller to be freely set to be long, the number of rotations of the paper feed roller during paper feeding may be increased. Up and down movement occurs for each rotation, and multiple rotations are impossible. Since the distance between the feed roller and the feed roller is restricted, and generally the positional relationship between the feed roller and the print unit is restricted, the feed roller, the feed roller and the print unit are moved along the paper transport direction. There is a problem that the linear arrangement results in a design condition, which increases the size of the printer, especially the installation area.

[0012]

According to the printer of the present invention, the paper stored in the paper feed cassette is sent forward one by one by being rotated by the rotational force of a drive motor, and the rollers are moved from the paper surface except when the paper is sent out. The paper feed roller that operates to stop the separation rotation, and the rotation of the paper feed roller by the rotational force of the drive motor rotates in the direction opposite to the paper transport direction when the leading edge of the transported paper arrives. In a printer having a feed roller that reverses the rotation direction by driving the drive motor in reverse and sends out the paper to the printing unit, the paper feed roller is provided above the paper feed cassette,
A first paper feed roller main body that rotates the paper stored in the paper feed cassette by a little less than one rotation and sends it forward by rotating the drive motor, and operates to separate from the paper surface of the paper except at the time of sending; A first paper feed roller driving unit for driving the first paper feed roller main body; and a first paper feed roller main body, which is provided near the paper feeding direction of the first paper feed roller main body and is rotated by the rotation of the drive motor. A second paper feed roller main body for receiving the paper conveyed from the first paper feed roller main body and sending the paper to the feed roller, and a second paper feed for driving the second paper feed roller main body A roller drive unit.

[0013] The first paper feed roller drive section includes the first paper feed roller drive section.
The paper feed roller body is immediately rotated at the start of the rotation of the drive motor, moved from the standby position to the sheet surface of the sheet below while rotating, and slightly rotated one turn to return to the upper standby position. Driving means for stopping the rotation and operating so as to continue the stopped state at this position until the start of the next sheet feeding operation is provided.

Further, the second paper feed roller driving section starts the rotation of the second paper feed roller main body immediately upon the start of the rotation of the drive motor, and stops the rotation when the drive motor reversely rotates next. And a driving unit for operating the printer so as to maintain the state until the next sheet feeding operation is started.

[0015]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a structural view showing a main part of an embodiment of the present invention, and FIG. 2 is a front view, (b) side view, and (c) showing a main part of a paper feed roller driving unit in FIG.
FIG. 3 is a partial cross-sectional view, FIG. 3 is a side view showing an operation process of a first driving roller driving unit in FIG. 1, and FIG. 4 is a side view showing an operation process of a second paper feeding roller driving unit in FIG. In each figure, gears are indicated by circles, and gears particularly important for explanation of operation are indicated by bold circles. The rotation direction of each gear is indicated by an arrow.

In FIG. 1, the printer of the present invention is provided above a paper feed cassette 8 containing a plurality of papers, and rotates the paper stored in the paper feed cassette 8 once by rotating a drive motor (not shown). The feed roller body 1 is rotated slightly and sent forward, and the feed roller body 1 is operated to move away from the sheet surface of the feed cassette 8 except at the time of the feed, and a gear group for driving the feed roller body 1. Paper roller drive unit 3,
A paper feed roller main body 2 provided near the paper feed direction of the paper feed roller main body 1 and rotated by the rotation of the drive motor to receive the paper conveyed from the paper feed roller main body 1 and send it to the feed roller 5; And a feed roller driving unit 4 composed of a gear group for driving the feed roller main body 2.

Next, the outline of the operation will be described. The drive motor is started by receiving a start signal of a printing operation of the printer from a control unit (not shown). The paper feed roller 1 is at an upper position away from the surface of the paper 7 in the paper feed cassette 8 during standby,
Down on paper 7 while rotating by starting drive motor 1
The rotation of the sheet 7 is slightly reduced, returns to the upper position away from the sheet surface of the sheet 7, and stops rotating. The paper 7 is fed forward by this distance by the rotation operation of the paper feed roller 1 which is slightly less than one rotation.

Since the paper feed roller 2 is rotated by the activation of the drive motor, the paper conveyed by the paper feed roller 1 is transferred to the feed roller 5.

The feed roller 5 receives the paper conveyed from the paper feed roller 2. At this time, the feed roller 5 rotates in the direction opposite to the paper conveyance direction. This is to ensure that the leading edge of the conveyed paper is pressed against the roller surface, so that the conveyed paper is fed to the feed roller 5.
Can definitely be supplemented. At this point, the control unit detects the paper position and issues a control signal to reverse the rotation direction of the drive motor. As a result, the feed roller 5 sends out the paper whose switching direction changes to the paper transport direction to the printing unit 6.

On the other hand, when the rotation of the drive motor is reversed, the paper feed roller main body 2 stops rotating and becomes free, and the paper feed roller main body 1 enters a standby state.

Next, the details of the feed roller driving units 3 and 4 constituting the feed unit will be described with reference to FIG. 2A is a front view of the paper feeding unit, FIG. 2B is a side view of the paper feeding unit, and FIG.
FIG. 2 is a partial sectional view of FIG. FIG. 2B will be described with reference to FIG. In this drawing, the paper feeding unit is in a standby state.

The paper feed roller driving section 3 includes a main gear 31 to which a rotational driving force of a driving motor (not shown) is transmitted, and a sub gear 32 formed coaxially with the main gear 31 and integrally rotating with the main gear 31. A swinging plate 33 swinging by the rotation of the main gear 31, a thick swinging gear 34 and a thin swinging gear 35 rotatably supported by the swinging plate 33 and always meshing with the sub gear 32. An intermediate gear 36 rotatably supported by the same rocking plate 33 and having the same thickness as the rocking gear 35 and always meshing therewith; a feed roller driving gear 39 for transmitting a rotational driving force to the feed roller 1; A transmission gear 37 which always meshes with the paper roller drive gear 39, and which is formed coaxially with the transmission gear 37, rotates integrally with the transmission gear 37, and is selectively provided with the swing gear 34 or the intermediate gear 36, that is, the supply of the drive motor. In the case of forward rotation, the gear is engaged with the oscillating gear 34 and in the case of reverse rotation, the intermediate gear 36 is meshed with the oscillating gear 34. 37a, a sub-transmission gear 37 'having the same width as the thickness of the intermediate gear 36 and having a tooth extraction portion 37b with a missing tooth, and a paper feeder which is mounted coaxially with the paper feed roller 1 and rotates by the paper feed roller 1. Two pawls 38 for moving the roller 1 up and down and temporarily stopping rotation
a, 38b.

The transmission gear 37, the sub transmission gear 37 '
FIG. 2 shows the meshing state of the gears with the intermediate gear 36 and the driving gear 39.
This is as shown in FIG.

Subsequently, the feed roller driving unit 4 includes a main gear 41 to which the rotational driving force of the driving motor is transmitted, and a main gear 41 formed coaxially with the main gear 41.
1, a swinging plate 44 swinging by the rotation of the main gear 41, a swinging gear 43 supported by the swinging plate 44 and constantly meshing with the subgear 42, and a swinging gear 43. A paper feed roller driving gear 45 that drives the paper feed roller 2 so that the drive motor meshes when the rotation of the drive motor starts at the time of paper feeding and the meshing is released by the reverse rotation of the drive motor.

Further, the second paper feed roller driving section 4 includes:
A paper feed roller drive gear 45 to which the rotational drive force of the drive motor is transmitted, and a cylindrical coil spring formed so as to rotate integrally with the paper feed roller drive gear 45, and a paper feed roller 2 rotating shaft in a hollow portion thereof. When the drive motor is inserted and starts rotating at the start of the paper feeding operation, the coil spring tightens the rotation shaft of the paper feed roller 2 to transmit the rotation, and when the drive motor rotates reversely, loosens the tightening of the coil spring. A configuration using a coil clutch (not shown) that does not transmit rotation may be used. In this way, the number of constituent gears can be reduced.

Next, the detailed operation of the paper feed roller 1 will be described with reference to FIG. FIG. 3A shows the state at the start of the sheet feeding operation. Before that, first, the main gear 31 starts rotating in the direction of the arrow by the activation of the drive motor (not shown).
The swing plate 33 swings from the standby state shown in FIG. When the rotation continues, the pawl 38b of the cam 38 comes off and slides on the stopper 40 to move the paper feed roller 1 downward, the paper feed roller 1 comes into contact with the paper surface, and the paper starts to be fed forward. FIG. 3B shows the state during paper feeding.
Shown in

Subsequently, when the paper feed roller 1 comes before making one rotation, the paper feed roller 1 is moved upward again by the cam 38, and the paper feed operation is completed. At this time, the pawl portion 38a of the cam 38 reaches the position where it engages with the stopper 40, and the toothed portion 37a of the sub-transmission gear 37 'has just reached the point of engagement with the oscillating gear 34. Is not transmitted, and the feed roller 1 stops rotating. FIG. 3C shows a state at the time of completion of the sheet feeding operation.

Subsequently, the driving motor for the paper sent out to reach the feed roller 5 via the paper feed roller 2 rotates in the reverse direction.
The main gear 31 rotates in the reverse direction, the swing plate 33 swings downward, and the intermediate gear 36 meshes with the sub-transmission gear 37 ′ to slightly rotate the sheet feeding roller 1, but the claw portion 38 b of the cam 38 and the stopper 40 At the position where the gears mesh with each other, the toothed portion 37b of the sub gear 37 'reaches the meshing point, the rotation is not transmitted, and the paper feed roller 1 stops again. The state after the reverse rotation of the drive motor is shown in FIG. The reason why the paper feed roller 1 is slightly rotated after the reverse rotation is to move the tooth extraction portion 37a of the transmission sub gear 37 'to enable the next paper feed operation and to be in a standby state.

Next, the detailed operation of the sheet feeding roller driving section 4 will be described with reference to FIG. FIG. 4A shows a state at the time of standby,
In this state, when a driving motor (not shown) is started by the start of sheet feeding, the main gear 42 starts rotating, the swinging plate 44 swings, and the swinging gear 43 meshes with the driving gear 45 to transmit the rotation to feed. The paper roller 2 starts rotating. And feed roller 1
When the paper conveyed from the printer arrives, it is transferred to the next feed roller 5. FIG. 4B shows the state at the time of paper feeding. When the paper reaches the feed roller and the drive motor rotates in the reverse direction, the main gear 41 rotates in the opposite direction, swings until the swing plate 44 hits the stopper 46, separates the swing gear 43, and sets the feed roller 2 to the free state. I do. That is, the gear
It operates to return to the standby state of (1).

[0030]

As described above, in the printer of the present invention, the paper feed roller is constituted by two paper feed rollers, and the paper in the paper feed cassette is first sent out by the first paper feed roller by one rotation. Then, the second paper feed roller transports the paper to the feed roller, and the first paper feed roller waits until the next paper feed operation with the paper feed roller raised and stopped. By increasing the number of rotations of the second paper feed roller, the distance from the paper feed roller to the feed roller can be increased. By utilizing this, for example, as shown in the embodiment, it is possible to arrange the feed roller and the printing unit in a three-dimensional manner by making the paper conveyance path a U-shape, so that the printer dimensions,
In particular, there is an effect that the installation area can be reduced.

Although the second paper feed roller stops rotating after paper feed and only enters a free state and does not move up and down, the paper feed accuracy is substantially equal to that of the first paper feed roller for feeding out the paper on the paper feed cassette. Since this is determined, this does not significantly affect the feeding accuracy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a structural concept of a main part of an embodiment of the present invention.

2A is a front view, FIG. 2B is a side view, and FIG.

FIG. 3 is a side view illustrating an operation process of a first sheet feed roller driving unit in FIG. 2;

FIG. 4 is a side view illustrating an operation process of a second paper feed roller driving unit in FIG. 2;

FIG. 5 is a configuration diagram showing a structural concept of a main part of a conventional example.

FIG. 6 is a side view illustrating an operation process of the sheet feeding roller driving unit in FIG.

[Explanation of symbols]

 1, 2 paper feed roller 3, 4 paper feed roller drive unit 5 feed roller 6 printing unit 7 paper 8 paper feed cassette 31 main gear 32 sub gear 33 rocking plates 34, 35 rocking gear 36 intermediate gear 37 transmission gear 37 'sub Transmission gear 38 Cam 39 Feed roller drive gear 40 Stopper 41 Main gear 42 Sub gear 43 Swing gear 44 Swing plate 45 Feed roller drive gear 46 Stopper

Claims (6)

[Claims] 1. A feeding device which operates by rotating by a rotational force of a drive motor to send out the sheets stored in a sheet feeding cassette one by one and to separate the rollers from the sheet surface to stop the rotation except when sending out. When the paper feed roller is rotated by the rotational force of the paper motor and the drive motor, the paper feed roller rotates in the opposite direction to the paper transport direction, and when the leading end of the transported paper arrives, the drive motor rotates in the reverse direction to rotate. And a feed roller for inverting and feeding the sheet to a printing unit, wherein the sheet feed roller is provided on an upper portion of the sheet feed cassette, and the sheet stored in the sheet feed cassette by rotation of the drive motor. Is rotated slightly less than one turn, and is sent forward. The first sheet feeding roller body that operates so as to be separated from the sheet surface of the sheet except at the time of sending the sheet, and drives the first sheet feeding roller body. A first paper feed roller driving section, and a first paper feed roller main body, which is provided in the vicinity of the paper feeding direction of the first paper feed roller body, is rotated by the rotation of the drive motor, and is conveyed from the first paper feed roller main body. A printer comprising: a second paper feed roller main body that receives a sheet and sends it to the feed roller; and a second paper feed roller drive section that drives the second paper feed roller main body. . 2. The first paper feed roller driving section rotates the first paper feed roller main body immediately upon the start of rotation of the drive motor, and rotates the first paper feed roller main body under the standby position while rotating. And a driving means for operating the surface so as to rotate it slightly less than one turn, return to the standby position above, stop the rotation, and continue the stop state at this position until the start of the next sheet feeding operation. The printer according to claim 1, wherein: 3. The second paper feed roller driving section starts the rotation of the second paper feed roller main body immediately upon the start of rotation of the drive motor, and then stops the rotation when the drive motor reversely rotates. 3. The printer according to claim 1, further comprising a driving unit configured to operate the printer in a free state, and to maintain the state until the next sheet feeding operation is started. 4. The first paper feed roller driving unit includes: a main gear to which a rotational driving force of the driving motor is transmitted; a sub gear formed coaxially with the main gear and integrally rotating with the main gear; An oscillating plate that oscillates by rotation of the main gear, a thick first oscillating gear and a thin second oscillating gear rotatably supported by the oscillating plate and always meshing with the sub-gear; An intermediate gear which is rotatably supported by the rocking plate and has the same thickness as the second rocking gear and always meshes therewith; and a feed roller drive for transmitting a rotational driving force to the first feed roller main body. A gear, a transmission gear that always meshes with the paper feed roller driving gear, and formed coaxially with the transmission gear to rotate integrally with the transmission gear and selectively with the first swing gear or the intermediate gear, that is, Forward when the drive motor rotates forward In the case of reverse rotation with the first oscillating gear, the first gear is engaged with the intermediate gear to temporarily stop the rotation of the first oscillating gear, and the rotation of the intermediate gear is temporarily stopped. A first transmission roller body mounted coaxially with the first paper supply roller main body and integrally operating with the first paper supply roller main body; A first for moving the main body up and down to temporarily stop the rotation of the first swing gear or the intermediate gear;
2. The printer according to claim 1, further comprising a cam having a second claw portion and a second claw portion. 5. The second paper feed roller driving section includes: a main gear to which a rotational driving force of the driving motor is transmitted; a sub gear formed coaxially with the main gear and integrally rotating with the main gear; A swinging plate that swings by the rotation of the main gear, a swinging gear that is supported by the swinging plate and always meshes with the sub-gear, and meshes with the swinging gear when the drive motor starts rotating at the time of sheet feeding. And a sheet feeding roller driving gear formed coaxially with the second sheet feeding roller body and disengaged by the reverse rotation of the driving motor, and integrally rotating with the second sheet feeding roller body. Item 6. The printer according to Item 1 or 3. 6. A paper feed roller driving gear to which a rotational driving force of the driving motor is transmitted, and a second paper feed roller driving unit integrally rotates with the paper feed roller driving gear by a cylindrical coil spring. When the rotation shaft of the second paper feed roller main body is inserted into the hollow portion and the drive motor starts rotating at the start of the paper feeding operation, the coil spring tightens the rotation shaft to transmit the rotation. 4. The printer according to claim 1, further comprising a coil clutch that loosens tightening of the coil spring and does not transmit rotation when the drive motor rotates in the reverse direction.