JPH1135165A - Paper feeding mechanism for printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change an inclination angle of a separation plate properly in compliance with a sort of paper and to surely separate a paper sheet so as to feed the paper sheet appropriately. SOLUTION: A separation plate 14, which separates paper sheets 2 one by one to place it on a paper mounting plate 9 part, is arranged so that its inclination angle can be changed, while a paper feeding roller 18, which feeds the paper sheet 2 housed on the paper sheet mounting plate 9, is arranged, and in the driving shaft part of the paper feeding roller 18, an angle changing cam 19 provided with a major diameter part and a minor diameter part is arranged. A driven can 16 following the outer circumferential face of the angle changing cam 19 is installed on the separation plate 14 integrally. When the angle changing cam 19 is moved in the axial direction so as to let the driven cam 16 selectively follow the major/minor diameter part of the angle changing cam 19, an inclination angle of the separation plate 4 is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed mechanism of a printer, and more particularly, to a paper feed mechanism of a printer capable of automatically feeding a plurality of sheets and easily feeding a sheet manually. About.

[0002]

2. Description of the Related Art Generally, a thermal transfer printer, an output device such as a computer, a word processor, a facsimile, etc., is used.
Various printers such as page printers are used.

[0005] FIG. 15 shows such a conventional printer.
The printer 50 is configured to be conveyed substantially horizontally from the rear to the front to perform printing, and the printer 50 has a printer frame 52 disposed inside a printer case (not shown). Below the printer frame 52, a platen 53 having a flat plate shape and extending in the width direction of the printer frame 52 is disposed so that its recording surface is directed upward.

On one side of the printer frame 52, there is provided a carriage 54 which is reciprocally movable along a platen 53 by a driving mechanism (not shown).
A thermal head (not shown) is provided at the lower end of the carriage 54 so as to be able to freely contact and separate from the platen 53. Further, a ribbon cassette (not shown) in which an ink ribbon of a desired color is wound is mounted in the carriage 54 in a detachable manner.
In a state where the paper 51 and the ink ribbon are supplied between the thermal head 3 and the thermal head, the thermal head is
The recording position is the pressure contact position between the thermal head and the platen 53 in the head down state.

A cassette mounting table 55 is disposed below the printer frame 52 on the upstream side in the paper transport direction. On the upper surface of the cassette mounting table 55, a plurality of sheets 51 are stacked inside. Paper cassette 56 for storing
Are detachably mounted. At the leading end of the paper feed cassette 56, a separating plate 57 for contacting the leading edge of the paper 51 and separating only the uppermost paper 51 of the stacked papers 51 is inclined at a predetermined angle. It is arranged in.

Above the cassette mounting table 55, a plurality of paper feed rollers 58 having a substantially D-shaped cross section are disposed so as to have a predetermined interval in the axial direction. It is urged by an urging member in a direction in which it comes into contact with a sheet feeding cassette 56 mounted on the cassette mounting table 55. A plurality of paper feed rollers 59 are arranged at a predetermined interval upstream of the platen 53 of the printer frame 52 in the paper transport direction, and above each paper feed roller 59, a paper feed roller 59 is provided. An auxiliary roller 60 which is in contact with the outer peripheral surface of the roller and is driven and rotated by the paper feed roller 59 is rotatably disposed.

Further, a plurality of paper discharge rollers 61 for discharging the paper 51 on which recording has been completed are disposed at predetermined intervals downstream of the platen 53 of the printer frame 52 in the paper transport direction.

In such a conventional printer 50, a plurality of sheets 51 are stacked and stored in a sheet cassette 56, and the sheet cassette 56 Then, the paper feed rollers 58 are brought into contact with each other to rotate the paper feed rollers 58, so that the paper sheets 51 stored in the paper feed cassette 56 are separated and fed one by one by a separation plate 57. ing.

The paper 51 fed by the paper feed roller 58 is transferred to the paper feed roller 59 and the auxiliary roller 60 just before the recording position, and is held between the paper feed roller 59 and the auxiliary roller 60. The recording paper 51 is discharged to the outside of the printer 50 by the paper discharge rollers 61.

FIG. 16 shows another conventional printer. In this printer 50, paper 51 is
The printer frame 52 is configured to convey in a curved manner from the rear to the upper side to perform recording. A platen 53 having a flat plate shape is disposed on the printer frame 52 such that the recording surface faces forward. ing. Further, on one side of the printer frame 52, a carriage 54 on which a thermal head is mounted and a ribbon cassette is detachably mounted is provided.

On the upstream side of the printer frame 52 in the paper transport direction, a paper mounting table 62 for stacking and mounting a plurality of papers 51 on the upper surface is swingable up and down around the rear end. A separation plate 57 is disposed at the leading end of the sheet mounting table 62 so as to be inclined at a predetermined angle.

A plurality of paper feed rollers 58 are disposed above the paper mounting table 62 so as to have a predetermined interval in the axial direction. A plurality of paper feed rollers 58 are provided below the platen 53 of the printer frame 52. A feed roller 59 is disposed at a predetermined interval, and an auxiliary roller 60, which is in contact with the outer peripheral surface of the paper feed roller 59 and is driven to rotate by the paper feed roller 59, is provided in front of each paper feed roller 59. It is arranged freely.

In such a conventional printer 50 as well, by rotating the paper feed roller 58 in the same manner as the printer 50 shown in FIG.
The sheets 51 stored in the sheet 2 are separated and fed one by one by a separation plate 57, conveyed to a recording position by a sheet feed roller 59 and an auxiliary roller 60, and the sheet 51 after recording is discharged upward. It is supposed to be.

[0014]

However, in the above-described conventional printer 50, the separation plate 57 is held so as to have a predetermined angle. For example, a thin sheet 51 such as a cut sheet is inclined. While keeping the angle small, for example, a thick paper 51 such as a postcard can maintain a large inclination angle so that the stacked sheets 51
However, since any of the printers 50 has a structure in which the inclination angle of the separation plate 57 is switched by manually operating a lever, the operation is troublesome. Moreover, the separation plate 5
If the inclination angle of 7 is erroneously set, there is a problem that the paper 51 cannot be reliably separated, and that the proper paper feeding cannot be performed.

The present invention has been made in view of these points, and the inclination angle of the separation plate can be appropriately changed according to the type of paper, and the paper can be reliably separated.
It is an object of the present invention to provide a paper feeding mechanism of a printer that can perform appropriate paper feeding.

[0016]

According to a first aspect of the present invention, there is provided a paper feed mechanism for a printer according to the present invention.
At the rear of the printer, there is provided a paper loading plate for stacking and storing a plurality of papers, and a separation plate for separating the paper one by one by contacting the leading edge of the paper with the paper loading plate portion. A paper feed roller which is arranged so as to be capable of changing its inclination angle and which can be brought into contact with the paper stored in the paper mounting plate and feeds the paper one by one; An angle changing cam having a plurality of cams with different diameters formed on the peripheral surface is arranged on the drive shaft portion so as to be rotatable integrally with the paper feed roller and to be movable in the axial direction, and the separation plate A driven cam that follows the outer peripheral surface of the angle changing cam is attached integrally,
The tilt angle of the separation plate is changed by moving the angle changing cam in the axial direction and causing the driven cam to selectively follow the cam of each stage of the angle changing cam. Things.

According to the first aspect of the present invention, the angle changing cam is moved in the axial direction according to the type of the paper, and the driven cam of the separation plate is selectively provided to the cam of each stage of the angle changing cam. By following, the inclination angle of the separation plate can be automatically changed, so there is no need to manually switch the inclination angle of the separation plate according to the type of paper,
The sheet can be reliably separated according to the type of sheet, and only the top sheet can be properly fed.

The invention described in claim 2 is the same as the invention described in claim 1.
In the above, a paper guide movable in the width direction of the paper mounting plate is disposed on the paper mounting plate, and the movement of the paper guide causes the angle changing cam to move in the axial direction, thereby causing the driven cam to move. It is characterized in that a cam of each stage to follow is selected.

According to the second aspect of the present invention, it is possible to select the cam of each stage of the angle changing cam simply by moving the paper guide, and to easily switch the inclination angle of the separation plate. Can be done.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

FIGS. 1 to 3 show an embodiment of a printer to which a paper feeding mechanism according to the present invention is applied. A printer 1 according to the present embodiment conveys a paper 2 almost horizontally and performs recording. The printer 1 is configured to
The printer has a printer frame 3 disposed inside a printer case (not shown). Below the printer frame 3, a platen 4 having a flat plate shape and extending in the width direction of the printer frame 3 is disposed so that its recording surface is directed upward. A carriage 5 reciprocally movable along a platen 4 by a drive mechanism (not shown) is provided on one side of the printer frame 3. A thermal head (not shown) as a recording head in which the heating elements are arranged and arranged is disposed so as to be able to freely contact and separate from the platen 4. Further, a ribbon cassette (not shown) in which an ink ribbon of a desired color is wound is mounted in the carriage 5 in a detachable manner. The heating element is guided between the platen 4 and the heating element. Then, with the paper 2 and the ink ribbon supplied between the platen 4 and the thermal head, the thermal head is pressed against the platen 4, and the pressure contact position between the thermal head and the platen 4 in the head down state is recorded. Position.

A paper transport path 6 is formed below the printer frame 3 and communicates in a substantially straight line in the front-rear direction. A front portion of the paper transport path 6 is a paper insertion port 7. I have. Further, a guide plate 8 is disposed at an upper portion on the rear side of the paper transport path 6 so as to have a predetermined gap with respect to the lower surface of the paper transport path 6.

Above the guide plate 8, a paper placing plate 9 which is arranged so as to be inclined so that the rear is high, is disposed so as to be vertically swingable about its rear end. A spring 10 is interposed between the front lower surface of the sheet mounting plate 9 and the guide plate 8, and the sheet mounting plate 9 is always moved upward by the urging force of the spring 10. Is held in. Further, the sheet placing plate 9 is provided with the sheet placing plate 9.
A pair of paper guides 11, 11 erected at substantially right angles and extending in the front-rear direction, are respectively movably arranged in the width direction of the paper mounting plate 9.
An insertion guide 12 that appropriately guides a plurality of stacked sheets 2 inserted between the respective sheet guides 11 to the upper surface of the sheet mounting plate 9 is formed on a surface facing each other. . Further, a cam receiving recess 13 is formed so as to protrude from one end side (left side in the figure) of the paper placing plate 9.

In the vicinity of the leading end of the paper placing plate 9 of the guide plate 8, the stacked paper 2 extends along the paper placing plate 9 and abuts on the leading edge of the paper 2. A separation plate 14 for separating only the uppermost sheet 2 is provided, and the separation plate 14 is rotatable about a substantially central portion in the front-rear direction. The inclination angle can be changed.
As shown in FIG. 4, an urging spring 15 is attached to the separation plate 14.
In FIG. 4, it is always urged in the direction of turning clockwise. Further, a driven cam projection 16 projecting upward is integrally formed on one end side of the separation plate 14.

A paper feed roller drive shaft 17 extending in the width direction of the printer frame 3 and having both ends supported on both sides of the printer frame 3 is disposed above the paper mounting plate 9. The paper feed roller drive shaft 17 has a plurality of sections (in this embodiment, 2
) Are mounted so as to have a predetermined interval in the axial direction.

At one end of the feed roller drive shaft 17,
An angle changing cam 19 is provided so as to rotate integrally with the paper feed roller driving shaft 17 and to be movable in the axial direction. An end face of the angle changing cam 19 has a sheet guide 11 of the sheet loading plate 9. Is moved in a direction approaching the printer frame 3, a part of the end face of the paper guide 11 is brought into contact. The angle changing cam 1
Reference numeral 9 denotes a two-stage cam including a large-diameter portion 20 and a small-diameter portion 21, and a notch portion 22, which is partially cut away, is formed on the outer peripheral portion of the angle changing cam 19. Further, on the printer frame 3 side of the angle changing cam 19, a projecting cam 23 which is rotated integrally with the angle changing cam 19 and engages with the cam receiving recess 13 of the paper placing plate 9 is formed. With the engagement of 23 with the cam receiving recess 13, the paper mounting plate 9 swings downward against the urging force of the spring 10.

The angle changing cam 19 and the projection cam 2
2, an urging spring 24 is disposed, and the urging spring 24 causes the angle changing cam 19 to move along the axial direction in the normal state as shown in FIG. As shown in FIG. 3, the paper guide 11 is moved in a direction approaching the printer frame 3 so that a part of the end face of the paper guide 11 is brought into contact with the end face of the angle changing cam 19 as shown in FIG. The contact allows the angle changing cam 19 to move in the direction approaching the printer frame 3 against the urging force of the urging spring 24.

In this embodiment, as shown in FIG. 1, the state in which the projection cam 23 is engaged with the cam receiving recess 13 is set as a reference position, and in this reference position, the notch 22 of the angle changing cam 19 is set. Is the driven cam projection 1 of the separation plate 14
6 and thereby the angle changing cam 19
Are movable in the axial direction without contacting the driven cam projection 16. Then, as shown in FIG. 3, in a state where the angle changing cam 19 is held at a position separated from the printer frame 3 by the urging force of the urging spring 24, the driven cam projection 16 The angle changing cam 19 is located on the outer peripheral side of the diameter portion 20.
Is driven to rotate, and the driven cam projection 16
Following the large diameter portion 20, the driven cam projection 16 is largely pushed downward, thereby causing the separation plate 14 to move the urging spring 1
The separation plate 14 is rotated against the urging force of No. 5 and the separation plate 14 is held at a large inclination angle, so that a relatively thick sheet 2 such as a postcard can be fed. On the other hand, as shown in FIG. 2, a part of the end face of the paper guide 11 is brought into contact with the end face of the angle changing cam 19, and the angle changing cam 19 is attached to the printer frame 3 against the urging force of the urging spring 24. In a state where the driven cam projection 16 is held at the close position, the driven cam projection 16 is located on the outer peripheral side of the small diameter portion 21 of the angle changing cam 19, the angle changing cam 19 is driven to rotate, and the driven cam projection 16 Small diameter part 2 of change cam 19
When the follower 1 is followed, the driven cam projection 16 is pushed down slightly, whereby the separation plate 14 is rotated against the biasing force of the biasing spring 15 and the separation plate 14 is held at a small inclination angle. Thus, for example, it is possible to feed relatively thin paper 2 such as ordinary cut paper.

Near the printer frame 3 near the upstream side of the platen 4 in the sheet transport direction, the printer frame 3
A paper feed roller drive shaft 25 extending in the width direction and having both ends supported on both sides of the printer frame 3 is provided. The paper feed roller drive shaft 25 has a plurality of paper feed rollers 26, 26 are attached at predetermined intervals.
Further, above each paper feed roller 26, the paper feed roller 2 is provided.
An auxiliary roller 27 which is in contact with the outer peripheral surface of the roller 6 and is rotated by the paper feed roller 26 is rotatably disposed. In addition,
The paper feed roller 18 is arranged such that a gap is formed between a lower part thereof and a lower surface of the paper transport path 6 so that at least one sheet 2 can pass therethrough.

Further, on the rear side of the paper transport path 6,
A transport roller drive shaft 28 extending in the width direction of the printer frame 3 and having both ends supported on both sides of the printer frame 3 is provided. The transport roller drive shaft 28 includes a plurality of transport rollers 29. Are attached at predetermined intervals. Above each transport roller 29, an auxiliary roller 30 which is in contact with the outer peripheral surface of the transport roller 29 and is driven to rotate by the transport roller 29 is rotatably disposed.

The paper feed roller drive shaft 17 has a leading end extending rearward of the printer frame 3 located near the transport roller 29, and a leading end formed with an acute angle. A plate 31 is provided so as to be slightly swingable in the vertical direction.
Normally, the leading end of the sheet is held at a lower swinging position by its own weight so as to contact the lower surface of the sheet transport path 6.
The sheet switching plate 31 may be always urged to the lower swing position by a spring.

Further, between the front end portion of the guide plate 8 and the paper feed roller 26, the guide plate 8 and the paper feed roller 1 are provided.
8, a paper detection lever 32 is provided as a paper detection member that swings and detects the paper 2 when the paper 2 is conveyed. In addition, a paper detection lever 33 as a paper detection member that swings when the paper 2 is transported to the transport roller 29 and detects the paper 2 is disposed. In the present embodiment, a detection auxiliary lever 34 as a detection auxiliary member having a substantially L-shape is attached to the paper feed roller drive shaft 25 so as to be rotatable about the paper feed roller drive shaft 25. One end of the detection assist lever 34 is in contact with the leading end of the sheet detection lever 32, and the other end is located in the sheet conveyance path 6 at the lower end of the sheet feed roller 26. Then, this paper transport path 6
The sheet 2 is inserted into the sheet 2, and the detection auxiliary lever 34 is rotated by the sheet 2.
The sheet detecting lever 32 is pivoted by the leading end of the sheet 2 so that the presence or absence of the sheet 2 passing through the sheet conveying path 6 can also be detected.

Further, the platen 4 of the printer frame 3
The printer frame 3 is located further downstream in the paper transport direction.
A paper discharge roller drive shaft 35 extending in the width direction of the printer and supported by the printer frame 3 is rotatably disposed. The paper discharge roller drive shaft 35 discharges the paper 2 on which recording has been completed to the outside. A plurality of discharge rollers 36 are attached at predetermined intervals.

A drive motor (not shown) such as a stepping motor is disposed on one side of the printer frame 3. The rotation of the drive motor is controlled by a gear transmission mechanism 37 including a plurality of gears and shafts. Are transmitted to the feed roller drive shaft 17, the paper feed roller drive shaft 25, the transport roller drive shaft 28, and the discharge roller drive shaft 35, respectively. Further, in the present embodiment, a clutch lever is provided on one side surface of the printer frame 3. The gear transmission mechanism 37 can be switched so as not to transmit the transmission.

Next, the operation of the present embodiment having the above-described configuration will be described.

First, the case where paper is fed by the paper feed roller 18 will be described.

In the printer 1 according to this embodiment, in the normal state, as shown in FIGS. 1 and 7, the projection cam 23 is held at the reference position engaged with the cam receiving recess 13.

When the sheet 2 on which recording is to be performed is a sheet 2 such as a normal cut sheet, the sheet guide 11 is moved in a direction approaching the printer frame 3 as shown in FIG. Are made to abut against the end face of the angle changing cam 19, and the angle changing cam 19 is held at a position close to the printer frame 3 against the urging force of the urging spring 24. In this state, the driven cam projection 1
6 is located on the outer peripheral side of the small diameter portion 21 of the angle changing cam 19.

In this state, a plurality of sheets 2 of a desired size are stacked and placed between the sheet guides 11 on the upper surface of the sheet loading plate 9 and the clutch lever 38 is swung to supply the sheets. It is switched so that the paper roller drive shaft 17 is rotated.

Subsequently, by driving the drive motor to rotate the feed roller driving shaft 17 via the gear transmission mechanism 37, the feed roller 18 is driven to rotate as shown in FIGS. With the rotation of the paper feed roller 18, the angle changing cam 19 is rotated, the engagement between the projection cam 23 and the cam receiving recess 13 is released, and the paper mounting plate 9 swings upward by the urging force of the spring. The uppermost sheet 2 is brought into contact with the sheet feed roller 18. At the same time, angle change cam 1
9, the driven cam projection 16 of the separation plate 14 follows the small diameter portion 21 of the angle changing cam 19,
The driven cam projection 16 is pushed down slightly, whereby the separation plate 14 is rotated against the urging force of the urging spring 15, and the separation plate 14 is held at a small inclination angle.

The rotation of the paper feed roller 18 causes the uppermost sheet 2 to be conveyed by one sheet in the direction of the paper feed roller 26, and the sheet 2 is held by the separation plate 14 held at the small inclination angle. A load is applied to the leading edge of the paper 2 to separate and transport only the uppermost paper 2 smoothly.

When the paper 2 is thus fed, the presence or absence of the paper 2 is detected by the paper detection lever 32,
When the paper detection lever 32 detects that the paper 2 is present, it is determined that the paper 2 is properly fed, and the paper feeding operation is continued.

When the leading edge of the paper 2 reaches the contact portion between the paper feed roller 26 and the auxiliary roller 27, in this embodiment, the paper feed roller 26
Because it is rotated in the opposite direction to the transport direction of
The leading edge of the paper 2 hits the paper feed roller 26,
The leading edge of the paper 2 is aligned so as to be parallel to the paper feed roller 26, and the posture of the paper 2 is controlled.

Next, at the timing when the leading edge of the paper 2 is abutted against the paper feed roller 26 and the leading edge of the paper 2 is aligned in parallel with the contact portion between the paper feed roller 26 and the auxiliary roller 27, the rotation of the drive motor By switching the direction, the paper feed roller 26 is rotated counterclockwise in FIG. 4, and the paper feed roller 18 is rotated in the same direction as it is. 2 is transported between the platen 4 and the thermal head.

Then, by continuing the rotation of the paper feed roller 18, the angle changing cam 19 is held at the reference position and the projection cam 23 is engaged with the cam receiving recess 13 as shown in FIGS. The paper loading plate 9 is pivoted downward against the urging force of the spring, and the uppermost paper 2 and the paper feed roller 1
8 is released, and the paper feed roller 18 is held at a position separated from the paper 2. In this state, paper 2
Is projected from the platen 4 toward the paper discharge roller 36.

Thereafter, by driving the drive motor in the reverse direction, the paper feed roller 26 is rotated clockwise, whereby the paper 2 is transported in the reverse direction to the transport direction, and the cueing of the paper 2 is performed. In this case, the paper feed roller 18
Is held at a position separated from the sheet 2 as it is.

In this state, the thermal head is pressed against the platen 4 via the ink ribbon and the paper 2 to move the carriage 5 along the platen 4, and the heating element of the thermal head is moved based on a desired recording signal. By selectively driving, desired recording is performed on the paper 2. Then, the paper feed roller 26 is moved to the paper 2
, The paper feed accompanying the line feed operation required for recording is repeated.

When the recording on the sheet 2 is completed, the driving motor is driven to rotate normally and the discharge roller 36 is rotated to discharge the sheet 2 and complete the recording operation on one sheet 2. I do.

Then, the above operation is repeated, and the paper 2
Make a record at

Next, when printing on thick paper 2 such as a postcard, the angle changing cam 19 is attached by moving the paper guide 11 away from the printer frame 3 as shown in FIG. It is held at a position separated from the printer frame 3 by the urging force of the urging spring 24.
In this state, the driven cam protrusion 16 is
Are located on the outer peripheral side of the large-diameter portion 20.

In this state, when the drive motor is driven to rotate the feed roller drive shaft 17 via the gear transmission mechanism 37, the feed roller 18 is driven to rotate.
As shown in FIGS. 6 and 9, with the rotation of the paper feed roller 18, the angle changing cam 19 is rotated, and the projection cam 2 is rotated.
The engagement between the cam 3 and the cam receiving recess 13 is released, the sheet placing plate 9 is swung upward by the urging force of the spring, and the uppermost sheet 2 comes into contact with the sheet feeding roller 18. At the same time, the rotation driving of the angle changing cam 19 causes the driven cam projection 1
6 follows the large diameter portion 20 of the angle changing cam 19, so that the driven cam projection 16 is largely pushed downward, whereby the separation plate 14 is rotated against the urging force of the urging spring 15. The separation plate 14 is held with a large inclination angle.

The rotation of the paper feed roller 18 causes the uppermost sheet 2 to be conveyed by one sheet in the direction of the paper feed roller 26, and the sheet 2 is held by the separation plate 14 held at the large inclination angle. A load is applied to the leading edge of the paper 2 to separate and transport only the uppermost paper 2 smoothly.

Thereafter, similarly to the above-described operation, the paper 2 is conveyed and desired recording is performed by the thermal head.

Next, the case where the recording is performed by feeding the paper 2 manually will be described.

In this case, first, as shown in FIG.
The paper 2 is inserted from the paper insertion port 7 of the printer frame 3 into the paper transport path 6 until the leading end of the paper 2 abuts between the transport roller 29 and the auxiliary roller 30, and the clutch lever 38 is swung to feed the paper. The drive shaft 17 is switched so as not to rotate. At this time, the sheet switching plate 31 is slightly swung upward by the inserting operation of the sheet 2, and the sheet 2 can be inserted between the leading end of the sheet switching plate 31 and the lower surface of the sheet transport path 6. Are formed.

When the paper 2 is fed manually as described above, the detection auxiliary lever 34 is rotated to operate the paper detection lever 32, thereby detecting the presence or absence of the paper 2 and simultaneously detecting the presence or absence of the paper 2. The detection lever 33 detects the presence or absence of the sheet 2, and if the sheet detection levers 32 and 33 detect the presence of the sheet 2, it is determined that the sheet 2 is properly inserted, and the sheet feeding operation is performed. Is started. As described above, in the present embodiment, by using the detection auxiliary lever 34, one sheet detection lever 32
Thus, the presence or absence of the sheet 2 sent from the sheet mounting plate 9 and the sheet 2 sent from the sheet transport path 6 can be detected.

Then, the driving motor is driven to rotate the conveying roller driving shaft 28 clockwise in FIG.
When the is rotated, the paper 2 is transported backward along the paper transport path 6, and the transport roller 29 is stopped when the leading end of the paper 2 passes through the paper switching plate 31 as shown in FIG. In this state, the sheet switching plate 31 is swung downward by its own weight.

Subsequently, as shown in FIG. 13, the paper 2 is transported forward by rotating the transport roller 29 counterclockwise, and the transport direction of the paper 2 is switched by the paper switching plate 31. , Paper 2 is paper feed roller 2
6 is guided above the sheet switching plate 31.

The paper 2 is fed to the paper feed roller 26
The paper 2 is transported between the platen 4 and the thermal head by the rotation of the paper feed roller 26 and the transport roller 29.

Thereafter, as shown in FIG. 14, the sheet 2 is conveyed and desired recording is performed by a thermal head, as in the above operation.

Therefore, in this embodiment, the angle changing cam 19 is moved in the axial direction in accordance with the type of the paper 2, and the driven cam projection 16 of the separation plate 14 is moved.
By selectively following the large-diameter portion 20 or the small-diameter portion 21, the inclination angle of the separation plate 14 can be automatically changed. There is no need to switch the tilt angle of 14,
The paper 2 can be reliably separated according to the type of the paper 2 and only the uppermost paper 2 can be reliably fed.

Further, a paper insertion port 7 is provided at the front side of the printer 1, and the paper 2 is inserted from the paper insertion port 7 into the paper conveyance path 6.
, The paper is fed manually, so that the paper 2 stacked and mounted on the paper
Can be manually fed without removing the paper, and the manual paper 2 can be inserted from the front of the printer 1, so that the manual feeding of the paper 2 can be easily performed. .

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified as needed.

[0064]

As described above, the paper feeding mechanism of the printer according to the first aspect of the present invention is designed so that the paper feeding mechanism is adapted to the type of paper.
By moving the angle changing cam in the axial direction and making the follower cam of the separation plate selectively follow the cam of each stage of the angle changing cam, the inclination angle of the separation plate can be automatically changed. Therefore, it is not necessary to manually switch the inclination angle of the separation plate according to the type of paper, and the paper can be reliably separated according to the type of paper and only the uppermost paper can be properly fed.

According to the second aspect of the present invention, the cam of each stage of the angle changing cam can be selected only by moving the paper guide, and the inclination angle of the separation plate can be easily switched. It has effects such as being able to do.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a reference state showing an embodiment of a paper feeding mechanism of a printer according to the present invention.

FIG. 2 is a partial plan view showing a case where cut paper is fed in the paper feed mechanism of the present invention.

FIG. 3 is a partial plan view showing a case where a postcard sheet is fed in the paper feed mechanism of the present invention.

FIG. 4 is a vertical cross-sectional view illustrating a paper feed state by a paper feed roller when feeding cut paper in the paper feed mechanism of the present invention.

FIG. 5 is a vertical cross-sectional view showing a separated state of a feed roller when feeding cut paper in the paper feed mechanism of the present invention.

FIG. 6 is a vertical cross-sectional view showing a paper feed state by a paper feed roller when feeding a postcard sheet in the paper feed mechanism of the present invention.

FIG. 7 is an enlarged view of a paper feed roller showing a reference state of the paper feed mechanism of the present invention.

FIG. 8 is an enlarged view of a paper feed roller showing a state in which cut paper is fed in the paper feed mechanism of the present invention.

FIG. 9 is an enlarged view of a paper feed roller showing a state in which a postcard is fed in the paper feed mechanism of the present invention.

FIG. 10 is an enlarged view of a paper feed roller portion showing a separated state of the paper feed roller in the paper feed mechanism of the present invention.

FIG. 11 is a vertical cross-sectional view showing a paper insertion state in a manual paper feed operation of the paper feed mechanism of the present invention.

FIG. 12 is a vertical cross-sectional view showing a state in which a sheet is conveyed backward in a manual sheet feeding operation of the sheet feeding mechanism of the present invention.

FIG. 13 is a longitudinal sectional view showing a state in which a sheet is conveyed forward in a manual sheet feeding operation of the sheet feeding mechanism of the present invention.

FIG. 14 is a longitudinal sectional view illustrating a recording state of a sheet in a manual sheet feeding operation of the sheet feeding mechanism of the present invention.

FIG. 15 is a longitudinal sectional view showing a conventional printer.

FIG. 16 is a longitudinal sectional view showing another conventional printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer 2 Paper 3 Printer frame 4 Platen 5 Carriage 6 Paper conveyance path 7 Paper insertion port 9 Paper loading plate 11 Paper guide 13 Cam receiving recess 14 Separation plate 16 Follower cam projection 18 Paper feed roller 19 Angle change cam 20 Large diameter part Reference Signs List 21 small diameter portion 23 projection cam 26 paper feed roller 29 transport roller 31 paper switching plate 32, 33 paper detection lever 34 detection auxiliary lever 36 paper discharge roller

Claims (2)

[Claims] 1. A sheet mounting plate for stacking and storing a plurality of sheets is provided behind a printer, and the leading edge of the sheet abuts on the sheet mounting plate to separate the sheets one by one. And a paper feed roller for feeding the sheets one by one, which can be brought into contact with the sheets stored in the sheet mounting plate. A paper feed mechanism for a printer comprising: an angle changing cam having a plurality of cams having different diameters formed on a peripheral surface of a drive shaft portion of the paper feed roller, the angle changing cam being rotated integrally with the paper feed roller; The angle changing cam is disposed movably in the axial direction, a driven cam that follows the outer peripheral surface of the angle changing cam is integrally attached to the separating plate, and the angle changing cam is moved in the axial direction to change the driven cam to the angle changing cam. By selectively following the cams of the respective stages, A paper feed mechanism for a printer, wherein the inclination angle of the paper is changed. 2. A paper guide, which is movable in the width direction of the paper mounting plate, is disposed on the paper mounting plate, and the angle changing cam is moved in the axial direction by the movement of the paper guide. 2. The paper feed mechanism of a printer according to claim 1, wherein a cam of each stage that the driven cam follows is selected.