JPH09240865A - Paper feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the wear of the peripheral surface of a feed roller and cope with paper sheets with various thickness. SOLUTION: In a printer providing carry rollers 24, 25 for helping a paper sheet carrying by a separation roller 23, pressurizing plates 108, 109 for carrying press-contacted by the carry rollers 24, 25 are installed on a paper feed tray 2. Carry pads 120, 121 having a necessary and sufficient friction resistance for generating an auxiliary carrying force by the carry rollers 24, 25 are installed respectively on the upper surfaces 118, 119 of the pressurized plates 108, 109 for carrying. Therefore, the carry rollers 24, 25 are press-contacted to the pressured plate for carrying through carry pads 120, 121. Even at the use up time of the paper sheet, the wear of the peripheral surface of the carry rollers 24, 25 can be restrained. The auxiliary carrying force can be offered whichever thickness the paper is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device provided in an image forming apparatus such as a small printer for personal use.

[0002]

2. Description of the Related Art With the recent trend of downsizing of computers, individuals are often using personal computers (personal computers) or workstations on their desks. Along with this trend, there is a demand for a small printer that can be placed on a personal desk so that documents and tables created by a personal computer can be easily printed out.

In a small printer, the paper feeding mechanism also needs to be small. A technique related to the present invention for miniaturization is described in Japanese Utility Model Publication No. 4-12037. This publication discloses a paper feed mechanism including a separation roller and a conveyance auxiliary roller. More specifically, a pressing plate urged by a spring is pressed against the separation roller. The auxiliary roller is attached to the plate surface in a non-contact manner. That is, a recess is formed on the plate surface,
The auxiliary roller is fitted in the recess without contact. As a result, abrasion of the peripheral surface of the auxiliary roller can be suppressed, and the conveying force can be improved by making the paper elastic.

[0004]

By the way, on paper,
There are various types, from thick ones such as envelopes to thin ones such as tracing paper. However, with the technique disclosed in the above-mentioned official gazette, it is difficult to change the gap between the auxiliary roller and the plate surface each time depending on the sheet. Therefore, there are problems that the tracing paper can be conveyed but the envelope cannot be conveyed, and that the gap is too wide and the conveying force by the auxiliary roller is not substantially provided. Therefore, the technique disclosed in the above-mentioned official gazette has a problem that it cannot cope with sheets of various thicknesses.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned technical problems, to suppress abrasion of the peripheral surface of a roller for assisting sheet conveyance, and to cope with sheets of various thickness. Is to provide.

[0006]

In order to achieve the above object, the invention according to claim 1 is a sheet feeding device for feeding a sheet to a conveying path, and is a sheet placing device for placing a sheet. Section and a rotary shaft that is provided in a direction intersecting the paper transport path, rotates with the rotation of the rotary shaft, and selects the paper to be transported from the paper placed on the paper tray. A separation roller for taking out and sending the paper to the conveyance path, and a separation roller having a predetermined friction resistance for preventing a plurality of sheets from being taken out by the separation roller by being pressed against the separation roller with the conveyance path sandwiched therebetween. A pad, a transport roller attached to the rotary shaft, which rotates with the rotation of the rotary shaft, and which assists the transport of the sheet taken out from the sheet stacking section by the separating roller, and a transport path sandwiched between the transport rollers. Pressed A sheet feeding apparatus which comprises a conveying pad having a necessary and sufficient frictional resistance to cause auxiliary conveying force by the conveying rollers a sheet is conveyed in a state of pressing the conveying roller.

According to the present invention, a pad having a frictional resistance necessary and sufficient to generate an auxiliary conveying force required for assisting the sheet conveyance is pressed against the roller for assisting the sheet conveyance. It That is, since it is sufficient to generate an auxiliary carrying force, the frictional resistance of the pad can be set to a very small value. Therefore, even when the paper runs out, abrasion of the peripheral surface of the roller can be suppressed.

Moreover, since the roller for generating the auxiliary conveying force is pressed against the pad, the auxiliary conveying force can be reliably provided to the paper regardless of the thickness of the paper.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing a simplified external configuration of a printer according to an embodiment of the present invention, and FIGS. 2 and 3 are views showing the printer as viewed from the left side in order to explain the internal configuration of the printer. Is. In FIG. 2 and FIG. 3, in order to emphasize the internal configuration of the printer, the configuration relating to the external appearance is shown by a chain double-dashed line.

First, an outline and an external configuration of this printer will be described below. This printer is of a so-called personal use that is used by being placed on the desk of each individual. That is, this printer is connected to a personal computer (personal computer) or the like used by each individual, and is used for the purpose of easily printing out documents, tables and the like created by the individual on the personal computer.

As shown in FIGS. 1 to 3, this printer has a structure including an apparatus main body 1 and a paper feed tray 2.
The external appearance of the apparatus main body 1 is constituted by an openable / closable cover 3, and an upper housing 4 and a lower housing 5 which are fitted to each other. The paper feed tray 2 is for holding paper to be printed, and is removable from the apparatus body 1.

The cover 3 is, as shown in FIGS. 1 to 3,
It is attached to the apparatus main body 1 so as to cover the upper front part of the printer. The cover 3 can be opened in the direction of arrow A from the front surface of the printer toward the rear surface around the fulcrum portion 6. FIG. 3 shows a state in which the cover 3 is opened.
Note that it is preferable to remove the paper feed tray 2 when the cover 3 is opened.

A tray insertion port 7 is formed on the rear side of the cover 3. The paper feed tray 2 can be attached by inserting it into the tray insertion port 7, and can be removed by pulling it out from the tray insertion port 7.
A connector 8 is attached to the rear surface portion 4a of the upper housing 4. The connector 8 is for connecting this printer to a personal computer or the like. That is, the printer cable 9 having one end connected to the personal computer is connected to the connector 8.

As can be seen from FIGS. 2 and 3, the connector 8 and the printer cable 9 project from the rear surface portion 4a of the upper housing 4. The protrusion length L is
It is determined by the type of connector 8 and the type of printer cable 9 used. As shown in FIGS. 1 and 2, the paper feed tray 2 is shaped so as to extend obliquely upward and rearward from the apparatus main body 1 when inserted into the tray insertion port 7. The paper feed tray 2 has a size such that the upper end 2a thereof protrudes from the rear surface 4a of the upper housing 4 by a predetermined length when attached. Specifically, the projected image 11 of the upper end portion 2a of the paper feed tray 2 on the printer installation surface 10 is substantially the same as the protruding length L of the connector 8 and the printer cable 9 in the rear surface portion 4a of the upper housing 4.
It has a size that protrudes from it.

As described above, the protruding length L differs depending on the type of the connector 8 and the type of the printer cable 9 used, but here, the maximum protruding length is predicted and the size of the paper feed tray 2 is set. The shape and is designed. As a result, when installing the rear surface of this printer along the wall,
The operator does not collide the connector 8 and the printer cable 9 with the wall by setting the upper end 2a of the paper feed tray 2 as a reference and aligning the upper end 2a with the wall.
Therefore, it is possible to reduce the burden of installation work on the operator and prevent damage to the connector 8.

In addition, the printer installation surface 10 of the upper end 2a
The length of the projected image 11 with respect to the rear surface portion 4a of the upper housing 4 is determined by the length of the connector 8 and the printer cable 9.
Is almost the same as the protrusion length L of Therefore, it is possible to meet the demand for a smaller installation space. Next, the internal configuration of this printer will be described in detail mainly with reference to FIGS.

As shown in FIGS. 2 and 3, this printer is provided with a paper feeding section 20, a laser beam irradiation unit 30, an imaging unit 40, a developing unit 50, a transfer unit 60 and a fixing unit 70. A discharge port 80 is formed on the front surface of the printer. The discharge port 80 has an upper housing 4 and a lower housing 5.
It is formed near the boundary with.

The paper placed on the paper feed tray 2 is fed by the paper feed section 20, the imaging unit 40, the transfer unit 60, and the fixing unit 70 along the conveyance path 90 formed by the broken line on the apparatus main body 1. The sheets are sequentially conveyed, and finally discharged from the discharge port 80 to the outside of the apparatus. Transport route 90
2, is formed in a substantially straight line having a downward slope from the paper feed tray 2 toward the discharge port 80. This is because the shape is optimal for downsizing the printer.

The paper feed section 20 is for feeding the paper placed on the paper feed tray 2 to a conveyance path 90 formed in the apparatus main body 1. The paper feeding unit 20 is attached to the cover 3, and is lifted together with the cover 3 when the cover 3 is opened. The sheet feeding unit 20 is provided with a sheet feeding roller 21 (the sheet feeding roller 21 includes a separation roller and a conveyance roller as described later).
The paper feed roller 21 is provided at a position where it abuts the surface of the paper feed tray 2 when the paper feed tray 2 is inserted into the tray insertion port 7.

The paper feed section 20 is also provided with a paper detection switch 22. The paper detection switch 22 is for detecting the presence or absence of paper in order to perform paper feed control.
It is provided immediately downstream of the separation roller 21 in the transport path 90. Paper feed control is performed as follows. That is, when the sheet feeding is instructed while the sheet is placed on the sheet feeding tray 2, the sheet feeding roller 21 starts to rotate. As a result, the paper is taken out by the paper feed roller 21 and sent to the conveyance path 90. After the first predetermined time has elapsed from the start of rotation of the paper feed roller 21, the paper is
The paper detection switch 22 is reached. That is, the paper detection switch 22 is turned on.

The rotation of the paper feed roller 21 is stopped after a predetermined second time has elapsed since the paper detection switch 22 was turned on. During the second time, the supplied paper is the fixing unit 7.
It is set long enough to reach zero. The sheet that has reached the fixing unit 70 is conveyed and discharged by the fixing unit 70. When it is necessary to supply the next sheet, the sheet feeding roller 21 is rotated again after a lapse of a predetermined time from the rotation stop.

If the paper detection switch 22 does not turn on even after the first time has elapsed from the start of rotation of the paper feed roller 21, it is recognized that the paper is out. Laser light irradiation unit 3
0 is for outputting a laser beam corresponding to the image signal. The laser light irradiation unit 30 is provided in the lower housing 5 of the apparatus body 1.

The laser light irradiation unit 30 is provided with a laser light source 31 and an optical system 32. The laser light source 31 is composed of a semiconductor laser or the like. Optical system 3
2 is composed of a plurality of reflecting mirrors, lenses, polygon mirrors, and the like. The laser light generated by the laser light source 31 is applied to the imaging unit 40 via the optical system 32.

The laser light irradiation unit 30 has a connector 8
Is electrically connected to Laser light irradiation unit 30
From the personal computer to the printer cable 9 and connector 8
The irradiation light amount of the laser light and the like are determined on the basis of the image data given via the. Then, the laser light is generated from the laser light source 31 based on the determined irradiation amount of the laser light and the like.

The imaging unit 40, the developing unit 50 and the transfer unit 60 are for forming an image on the paper fed from the paper feeding section 20. In the imaging unit 40, the photoconductor 41 that is exposed by the above-mentioned laser light is installed. A charging charger 42 and a paper dust collecting brush 43 are provided along the periphery of the photoconductor 41. As the photoconductor 41, a small one having a diameter of 16 (mm) is used for downsizing of the printer.

The photosensitive member 41 rotates at a constant speed along the arrow B direction during image formation. After the surface of the photoconductor 41 is uniformly charged to a predetermined high potential by the charging charger 42,
It is exposed to laser light from the laser light irradiation unit 30. In the exposed area that receives the light, the electric charge in that area escapes to a low potential. As a result, an electrostatic latent image having a high potential region and a low potential region is formed on the surface of the photoconductor 41.

When the photoconductor 41 further rotates and the electrostatic latent image reaches the developing unit 50, the electrostatic latent image is developed into a toner image by the developing unit 50. Developing unit 50
Is provided in the upper housing 4 and includes a toner hopper 51,
The configuration includes the sub roller 52 and the developing roller 53. The toner hopper 51 is for filling the toner.

The sub roller 52 and the developing roller 53 are
They are rotated in the same direction as each other. By this rotation, the toner filled in the toner hopper 51 is frictionally charged,
Toner is electrostatically adsorbed on the peripheral surface. Sub roller 52
Are provided to more effectively triboelectrically charge the toner. The sub roller 52 and the developing roller 53 include
A predetermined bias voltage is applied. As a result, the toner attached to the peripheral surface of the developing roller 53 is electrostatically
It is adsorbed only on the exposed region of the surface of the photoconductor 41. So-called reversal development is performed. As a result, a toner image corresponding to the electrostatic latent image is formed on the surface of the photoconductor 41.

When the photoconductor 41 further rotates and the toner image reaches the transfer unit 60, the toner image is transferred onto the sheet conveyed along the conveying path 90. That is, the transfer roller 61 is incorporated in the transfer unit 60. The leading edge of the sheet is supplied between the photoconductor 41 and the transfer roller 61 in accordance with the leading edge of the toner image facing the transfer roller 61. As a result, the toner images formed on the photoconductor 41 are sequentially transferred to the paper.

The transfer unit 60 is attached to the cover 3, and is lifted together with the cover 3 when the cover 3 is opened. On the surface of the photoconductor 41 after transfer,
The toner that was not transferred to the paper remains. Further, when the paper comes into contact with the surface of the photoconductor 41, paper dust and the like generated from the paper also adhere to the surface of the photoconductor 41 together with the residual toner.

The paper dust attached to the photoconductor 41 is attached to the tip of the paper dust collecting brush 43 and collected when passing through the paper dust collecting brush 43 in the imaging unit 40.
Further, the residual toner adhering region of the photoconductor 41 is scattered and scattered by the tip of the paper dust collecting brush 43 when passing through the paper dust collecting brush 43, and the residual toner and the surface of the photoconductor 41 are separated from each other. The electrostatic coupling of is weakened. The residual toner having the weakened electrostatic coupling is collected by the developing roller 53 at the time of the next image formation.

The sheet after transfer is supplied to the fixing unit 70. The fixing unit 70 is for fixing the image transferred onto the sheet, and is provided along the transport path 90 between the upper housing 4 and the lower housing 5. The fixing unit 70 is divided into an upper fixing unit 71 and a lower fixing unit 72. The lower fixing unit 72 is fixed to the lower housing 5. The upper fixing unit 71 is rotatably attached to the lower fixing unit 72 by a fulcrum portion 73 in the arrow C direction.

A part of the conveying path 90 is formed between the upper fixing unit 71 and the lower fixing unit 72, and as described above, it is a straight line having a downward slope from the paper feed tray 2 toward the discharge port 80. Has been formed. Further, both units 71 and 72 are provided with an upper fixing roller 74 and a lower fixing roller 75, respectively. A heater (not shown) is provided inside the lower fixing roller 75 along the axis thereof.

The fixing unit 70 is in a closed state as shown in FIG. 2 when the cover 3 is closed. Specifically, the upper fixing unit 71 is pressed by the pressing portion 3a protruding from the inside of the cover 3. Here, the upper fixing roller 74 is attached to the upper fixing unit 71 so as to be displaceable in a direction orthogonal to the axial direction thereof. Then, it is always elastically urged by a spring or the like in the direction opposite to the arrow C direction. As a result, the upper fixing roller 74 is pressed against the lower fixing roller 75 and brought into pressure contact with a predetermined pressure.

The cover 3 is closed during image formation.
Further, the upper fixing roller 74 is rotated in the arrow D direction, and the lower fixing roller 75 is rotated in the arrow E direction. On the other hand, the sheet after transfer is supplied between the upper fixing roller 74 and the lower fixing roller 75 in this pressure contact state. At this time, the lower fixing roller 75 is heated by the heat of the heater. As a result, the toner image is melted by pressing and heating and is fixed on the paper.

The pressure contact state of the fixing unit 70 is released when the cover 3 is opened, as shown in FIG. That is, when the cover 3 is opened, the pressure contact state of the rollers 74 and 75 is released to facilitate the removal of the jammed paper. At this time, the rotation of the upper fixing unit 71 is restricted by the front surface portion 4b of the upper housing 4. The fixing unit 70 also includes an upper discharge roller 76 and a lower discharge roller 77. More specifically,
The upper discharge roller 76 is attached to the upper fixing unit 71, and is rotated in the arrow F direction (see FIG. 2). The lower discharge roller 77 is attached to the lower fixing unit 72, and is in the direction of arrow G (see FIG. 2).
It is something that can be rotated. Each discharge roller 76, 77
By the rotation of, the sheet after fixing is guided to the discharge port 80 and discharged to the outside of the apparatus.

Next, the structure relating to paper feeding will be described in more detail with reference to FIGS. FIG. 4 shows the paper feed tray 2 and the paper feed roller 2 provided in the paper feed unit 20.
It is a figure for demonstrating the structure of 1. The paper feed roller 21 provided in the paper feed unit 20 includes a separation roller 23 attached to the center of one rotation shaft 26 and two transport rollers 2 attached to both sides of the separation roller 23.
4 and 25 are included. The separation roller 23 and the transport rollers 24 and 25 have the same axial length.

The separation roller 23 is for taking out a sheet to be conveyed from the sheets placed on the sheet feed tray 2. The conveying rollers 24 and 25 are for providing an auxiliary conveying force to the sheet taken out by the separation roller 23 and realizing a smooth sheet supply to the conveying path 90. That is, since the smoothing sheet supply is insufficient with the conveying force of the separation roller 23, the conveying rollers 24 and 25 assist this.

The paper feed tray 2 is configured to include a bottom surface portion 100, a back surface portion 101 extending obliquely rearward with respect to the bottom surface portion 100, and guide portions 102 formed on both sides of the back surface portion 101. The sheet 103 is placed along the bottom surface portion 100 and the back surface portion 101, as indicated by the chain double-dashed line.
When the paper feed tray 2 is inserted into the tray insertion port 7 and paper is fed, the paper 103 is guided along the guide portion 102.

A separating pressure plate 104 is attached to the central position of the tip of the bottom portion 100. Separation pressure plate 10
Reference numeral 4 is attached to a position where the paper feed tray 2 comes into contact with the separation roller 23 when the paper feed tray 2 is inserted into the tray insertion port 7. The separating pressure plate 104 is for contacting the sheet with the separating roller 23 so that the separating roller 23 can take out the sheet.

The pressure plate for separation 104 is attached to the mounting portion 10.
5 is fixed to the bottom surface portion 100, and the main body portion 106 includes the separating spring 10 inserted between the bottom surface portion 100 and the main body 106.
It is urged upward by 7. As a result, with the paper feed tray 2 inserted into the tray insertion port 7, the separation pressure plate 104 and the separation roller 23 are in pressure contact.

At the tip of the bottom surface portion 100, and on the left and right sides of the separating pressure plate 104, two conveying pressure plates 108, 1 are provided.
09 is attached. Transport pressure plates 108, 10
The sheet feeding tray 9 is attached to a position where the sheet feeding tray 2 comes into contact with the transport rollers 24 and 25 when the sheet feeding tray 2 is inserted into the tray insertion port 7. The transfer pressure plates 108 and 109 are
This is to bring the sheet into contact with the transport rollers 24 and 25 in order to realize the assistance of the transport of the sheet by the transport rollers 24 and 25.

Further, in the conveying pressure plates 108 and 109, the mounting portions 110 and 111 are fixed to the bottom surface portion 100, like the separation pressure plate 104, and the main body portions 112 and 113 are the bottom surface portion 100 and the main body 112. It is urged upward by the transporting springs 114 and 115 that are inserted between the springs 113 and 113. As a result, in the state in which the paper feed tray 2 is inserted into the tray insertion port 7, the transport pressure plates 108 and 109 and the transport rollers 24 and 25 are in a pressure contact state.

Separation spring 107 and conveyance spring 114, 1
The biasing force is different from that of 15. As an example, the urging force of the separating spring 107 is the one of the conveying spring 11 more.
It is set to a value larger than the urging force of 4, 115.
This is because with respect to the pressure contact state between the roller and the pressure plate, a larger pressure contact force is required to take out the paper than to simply assist the paper conveyance.

The urging forces of the separating spring 107 and the conveying springs 114 and 115 may be determined in design according to the shape and the like. The urging force of the separating spring 107 and the conveying springs 114 and 115. May have the same value.
The separation pad 11 is provided on the upper surface 116 of the separation pressure plate 104.
7 is attached. The separation pad 117 is made of a material having a predetermined frictional resistance for preventing double feeding when the separation roller 23 takes out the sheet. For example, the separation pad 117 is made of silicone rubber,
Consists of urethane and cork.

The upper surface 11 of the transfer pressure plates 108 and 109
8 and 119 respectively include transport pads 120 and 121.
Is attached. The transport pads 120 and 121 are
The purpose of this is to reduce wear on the peripheral surfaces of the transport rollers 24, 25. On the other hand, the transport rollers 24 and 25 are for assisting the sheet transport by the separation roller 23 as described above. Therefore, if the frictional load is excessively applied to the conveyance rollers 24 and 25, the conveyance of the sheet will be hindered. for that reason,
The transport pads 120 and 121 are made of a flexible material having a frictional resistance necessary and sufficient to generate an auxiliary transport force by the transport rollers 24 and 25. Specifically, it is made of a material having a friction resistance smaller than that of the transport pressure plates 108 and 109. For example, the transport pads 120 and 121
Is composed of a PET film, a fluorine-based sheet, or the like.

FIG. 5 is a top view of the state in which the paper feed tray 2 is inserted into the tray insertion port 7. When the tip of the paper feed tray 2 is inserted into the tray insertion port 7, the separation roller 23 and the conveyance rollers 24 and 25 are separated from the separation pressure plate 104 and the conveyance via the separation pad 117 and the conveyance pads 120 and 121, respectively. Pressure plates 108, 10
9 is pressed. That is, the separating pressure plate 104 and the conveying pressure plates 108 and 109 are pushed downward by the separating roller 23 and the conveying rollers 24 and 25, as shown by the two-dot chain line and the solid line in FIG.

In this state, when the rotary shaft 26 is rotated to start feeding, the uppermost sheet of the sheets placed on the sheet feeding tray 2 is the separation roller 23 and the separation pad 117. Captured in the interim. One sheet is taken in because the separation pad 117 has a large friction resistance and the pressure contact state between the separation roller 23 and the separation pad 117 is relatively strong.

At the same time, the paper is conveyed by the transport rollers 24, 2.
5 is also taken in between the transfer pads 120 and 121. Then, the transport path 9 taken out from the paper feed tray 2
Sent to 0. The separation pad 117 with which the separation roller 23 is in pressure contact has a large frictional resistance as described above. As a result, a relatively large frictional resistance acts on the paper. Therefore, the conveyance force of the separation roller 23 is not sufficient for the smooth conveyance of the sheet. Therefore, the conveying force of the conveying rollers 24 and 25 is further applied to the separating roller 2
3 assists sheet conveyance.

When such paper feeding is repeated, the paper placed on the paper feed tray 2 may run out. As described above, the paper shortage is recognized when the paper detection switch 22 is not turned on even after the first time has elapsed from the start of the paper feed. During this time, the separation roller 23 and the transport rollers 24 and 25 rotate without being fed with paper.

On the other hand, the transport pressure plates 108, 109 are pressed against the transport rollers 24, 25 via the transport pads 120, 121 made of a material having a friction resistance smaller than that of the transport pressure plates 108, 109. ing. Therefore,
Abrasion of the peripheral surfaces of the transport rollers 24, 25 can be reduced as compared with the case where the transport rollers 24, 25 directly contact the transport pressure plates 108, 109.

Further, since the transport pressure plates 108 and 109 are pressed against the transport rollers 24 and 25 via the transport pads 120 and 121, an auxiliary transport force is applied to the paper regardless of the thickness of the paper. Can be reliably provided. Therefore, sheets of various thicknesses can be targeted for feeding.
Therefore, the printer can be easily used.

In the above description, the pressure plate 10 for separation is used.
4 and the pressure plates 108 and 109 for conveyance are separate members. However, for example, as shown in FIG. 6, the mounting portions 110, 11 of the pressure plates 108, 109 for transportation are attached.
1 is integrally molded, and the transport pressure plates 108 and 109 are
It may be one part. Further, for example, as shown in FIG. 7, the separation pad 117 and the transfer pads 120 and 121 are attached to one pressure plate 130, and the one pressure plate 13 is attached.
0 may be shared as the separating pressure plate and the conveying pressure plate. In this case, the urging force of the spring is the same between the separating pressure plate and the conveying pressure plate. Further, for example, as shown in FIG. 8, one pressure plate 131 has two notches 132,
133 is formed into a comb shape, and the cutout portions 132 and 133 are formed.
The three parts 134, 135, and 136 divided by may be used as the separating pressure plate and the conveying pressure plate, respectively.

With this structure, the separation pressure plate and the transport pressure plate can be easily attached to the paper feed tray 2. As a result, the burden on the operator can be reduced. Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various designs within the scope of technical matters described in other claims. It is possible to make changes.

[0055]

As described above, according to the present invention, the roller for assisting the sheet transportation is pressed against the pad having the frictional resistance necessary and sufficient to generate the auxiliary transportation force. In this case, wear of the peripheral surface of the roller can be suppressed. Therefore, the life of the roller can be extended.

Further, since the pad for pressing the roller for assisting the transportation of the paper is pressed, it is possible to reliably provide the auxiliary transportation force to the paper regardless of the thickness of the paper. Therefore, sheets of various thicknesses can be targeted for feeding. Therefore, the device can be easily used.

[Brief description of drawings]

FIG. 1 is a perspective view showing a simplified external configuration of a printer according to an embodiment of the present invention.

FIG. 2 is a diagram of the printer as viewed from the left side for explaining the internal configuration of the printer when the cover is closed.

FIG. 3 is a diagram of the printer viewed from the left side for explaining the internal configuration of the printer when the cover is opened.

FIG. 4 is a diagram illustrating a configuration related to sheet feeding.

FIG. 5 is a view from above showing a state in which a paper feed tray is inserted into the tray insertion port in order to further describe the configuration related to paper feed.

FIG. 6 is a plan view showing a simplified configuration of a pressure plate included in a paper feed tray according to another embodiment.

FIG. 7 is a plan view similarly showing a simplified structure of a pressure plate provided in a paper feed tray according to another embodiment.

FIG. 8 is a plan view similarly showing a simplified configuration of a pressure plate provided in a paper feed tray according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Device main body 2 Paper feed tray 7 Tray insertion slot 20 Paper feed section 23 Separation roller 24, 25 Conveying roller 26 Mounting shaft 70 Conveyance path 104 Separation pressure plate 105 Separation spring 106, 107 Conveyance pressure plate 108, 109 Conveyance Spring 117 Separation pad 120, 121 Transport pad

Claims (1)

[Claims] 1. A sheet feeding device for feeding a sheet to a conveying path, comprising: a sheet placing section for placing the sheet and a rotary shaft provided in a direction intersecting with the sheet conveying path. It is attached and rotates according to the rotation of the rotating shaft, takes out the paper to be conveyed from the paper placed on the paper tray, and conveys it to the separation roller and the separation roller for sending the paper to the conveyance path. A separation pad having a predetermined friction resistance for preventing a plurality of sheets of paper that are pressed against each other across the path and taken out by the separation roller; and a separation pad that is attached to the rotary shaft and rotates with the rotation of the rotary shaft. , A conveyance roller for assisting the conveyance of the sheet taken out from the sheet stacking section by the separation roller, and the conveyance roller that is pressed against the conveyance roller with the conveyance path sandwiched between the conveyance roller and the conveyance roller while being pressed against the conveyance roller. Sheet feeding apparatus comprising a conveying pad having an auxiliary necessary and sufficient frictional resistance to produce a conveying force that.