JPH05186078A - Image recorder - Google Patents

Abstract

PURPOSE:To prevent jam of paper sheets while simplifying a driving system of a paper sheet feed mechanism. CONSTITUTION:There are provided one-way motive power transmitting means 11 and 12 which transmit a driving force from a single rotational driving force generating source 4 to plural number of paper sheet feed rollers 21 and 22 through motive power transmitting means 31 and 35 to reverse the rotational direction and operate on the respective paper sheet feed rollers 21 and 22 in the inverse direction. The inside surfaces of outer peripheral side paper sheet guides 61, 62 and 63 of a conveying passage are formed in such a shape that outward projecting moderate curves are continued to each other. Thereby, the two paper sheet feed rollers 21 and 22 can be driven selectively by means of forward rotation or inverse rotation of the rotational driving force generating means 4. When paper sheets reach skew correcting members 71 and 72, they are pushed against the outer peripheral side paper sheet guides 61, 62 and 63, and the paper sheet feed rollers run idle, so that jam is never caused even if the paper sheets are conveyed excessively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus such as a printer, a facsimile, a copier, etc., and more particularly to a sheet feeding mechanism of an image recording apparatus having a multi-stage cut sheet storing section, that is, a sheet storing section as a sheet feeding means. Regarding

[0002]

2. Description of the Related Art In an image recording apparatus, it is necessary to separately convey and feed a sheet from a desired one of a plurality of sheet storage sections. As a power transmission system in a conventional paper feed unit, each paper feed roller is provided with an independent drive motor, and either drive motor is selectively driven to feed paper from a desired paper storage unit. There has been a roller equipped with a clutch that is turned on / off by an electric signal to transmit power, and one of the clutches is turned on to feed paper from a desired paper storage unit.

Further, Japanese Laid-Open Patent Publication No. 1-220660 discloses
The paper feed roller is rotated in a fixed direction to selectively separate and convey one of the papers in the plurality of paper storage units, and the paper is substantially inverted along the paper guide, and the paper skew correction member corrects the skew. It shows a method of recording an image on a sheet. In the conventional example of this type, as shown in FIG. 4, before the confluence of the conveyance path from the lower sheet storage section 52 to the sheet skew correction members 71 and 72 and the conveyance path from the upper sheet storage section. The transport path of No. 2 was formed like a straight line portion M.

[0004]

However, in the case of the first conventional example, a dedicated motor is required for each sheet feeding roller, and in the case of the second conventional example, the transmitted power is turned on / off by an electric signal. There is a problem that a dedicated clutch for turning off is required, which not only complicates the apparatus configuration but also causes a cost increase.

On the other hand, in the third conventional example, when the sheet is fed from the lower sheet storage section 52, the sheet skew correction members 71 and 72 are provided.
The distance between the sheet feeding roller 22 and the sheet feeding roller 22 is considerably longer than that in the case where the sheet is fed from the upper sheet storage section 51, and the rigidity of the sheet in between is significantly reduced. Paper skew correction member 7
When the sheet is struck against the sheet 1, 72 and the skew feeding correction is performed while the sheet is further transported by the sheet feeding roller, the sheet is transported along the sheet guide on the outer peripheral side of the transport path, and the skew feeding correction member 71,
Reach 72. As shown in FIG. 5, the sheet 522 in this state receives the conveying force H from the sheet feeding roller 22 and the reaction force I from the sheet skew correcting members 71 and 72. In the case of the conventional example, since the sheet conveying path has the straight portion M, when the sheet is further conveyed, the sheet receiving the force from the conveying roller and the skew feeding correcting member receives the force in the arrow K direction to the outside of the conveying path. It is pressed against or is buckled toward the inside of the conveyance path by receiving a force in the direction of arrow J. In the straight portion M of the paper transport path, whether the paper flexes outward and receives an outward force or the paper flexes inward and receives an inward force is a stochastic problem. If a paper jam is received, a paper jam will occur. When the paper is fed from the paper storage section on the lower side, the rigidity of the paper is significantly reduced, and thus there is a high possibility of a paper jam. This tendency becomes particularly noticeable at high humidity when the rigidity of the paper decreases. Therefore, a complicated control mechanism that can accurately control the sheet conveyance amount has also been required so as to prevent the sheet from being jammed and prevent a sheet jam.

It is an object of the present invention to provide an image recording apparatus provided with a paper feeding means capable of selectively feeding paper from a plurality of paper storages with a simple mechanical structure.

Another object of the present invention is to provide an image recording apparatus provided with a sheet feeding means capable of stably feeding a sheet without causing a sheet jam when the sheet is fed from a sheet storage section having a long transport path. Is.

[0008]

In order to achieve the above-mentioned object, the present invention has a plurality of paper storage units, and rotates a paper feed roller arranged in each paper storage unit in a predetermined direction. In an image recording apparatus that selectively separates and conveys a sheet from the sheet storage unit and records an image on the sheet, a bidirectionally rotatable driving force generation unit, and a driving force generation unit and a sheet feeding roller are provided. And a plurality of power transmission means for transmitting the driving force from the driving force generation means to the respective paper feed rollers in mutually reverse rotation directions, and the paper feed rollers arranged between the power transmission means and the paper feed roller. The present invention proposes an image recording apparatus including a one-way power transmission unit that rotates only in the predetermined direction.

It is also possible to reverse the order of arrangement of the power transmission means and the one-way power transmission means arranged between the driving force generation means and the paper feed roller.

Further, it is preferable to apply the present invention to the odd-numbered stages and the even-numbered stages of the plurality of sheet storage units.

When the plurality of power transmission means include a pair of gears, one power transmission means has an odd number of gears more than the other power transmission means.

More specifically, the one-way power transmission means is a one-way clutch, and the bidirectionally rotatable driving force generation means is a stepping motor.

The above-mentioned image recording apparatus can be applied as a recording means of an image to be printed by a printer, a recording means of a medical examination image of a facsimile, or a recording means of a document image of a copying machine.

The present invention further has a paper storage unit mounted on the main body of the image recording apparatus and a paper storage unit detachable from the main body, and the paper feed rollers arranged in the respective paper storage units are set in predetermined directions. In an image recording apparatus for rotating a sheet to selectively separate and convey a sheet from one of the sheet storage sections and to record an image on the sheet, a driving force generating means mounted on a main body and a supply of a detachable sheet storage section are provided. Between the power transmission means and the paper feed roller, the power transmission means is arranged between the paper roller and the drive force from the drive force generation means and transmits the drive force to the paper feed roller in a direction opposite to the rotation direction of the paper feed roller on the main body side. And a one-way power transmission means for rotating the paper feed roller only in a predetermined direction.

Also in this case, the arrangement order of the power transmission means and the one-way power transmission means can be reversed.

The plurality of paper storage units are a pair of odd-numbered and even-numbered paper cassettes. The present invention also has a plurality of paper storage units, a paper skew correction unit that corrects skew of the paper, and a paper guide that guides the paper from the plurality of paper storage units to the paper skew unit. The paper feed roller arranged in the paper storage unit is rotated in a predetermined direction to selectively separate and convey the paper from one of the paper storage units, and the paper is substantially inverted along the paper guide, and then the paper skew correction unit In an image recording device that corrects skew feeding of paper and feeds it, and records an image on the paper, change the inner shape of the outer side paper guide of the conveyance path from the lower paper storage section to the paper skew correction section. The present invention proposes an image recording apparatus which is formed to have a shape in which convex and smooth curves are connected to the outer peripheral side.

[0017]

In the present invention, when the rotational driving force generating means rotates in one of the bidirectional rotation directions, only one unidirectional power transmitting means of the two system power transmitting means transmits the power, and the other one The one-way power transmission means does not transmit power.
When the rotational driving force generating means rotates in the reverse direction, contrary to the above, only the other one-way power transmitting means transmits the power and one one-way power transmitting means does not transmit the power. The power transmission means is
Specifically, it is realized by a pair of gears, and the rotational driving force generating means drives the sheet feeding roller so that the sheet storing portions in the vertical direction are opposite to each other. Therefore, the driving force from the rotational driving force generating means is transmitted by the driving force transmitting means having a simple mechanical structure, so that the two sheet storage units can selectively feed the sheets.

When the respective one-way power transmission means are arranged coaxially with the paper feed roller, the structure of the power transmission means can be further simplified.

The rotation driving force generating means is a stepping motor and realizes bidirectional rotation.

Further, as shown in FIG.
Even when the paper feed roller 22 receives the conveyance force H from the paper feed roller 22 and the reaction force I from the sheet skew correction members 71 and 72, the inner shape of the paper guide on the outer peripheral side of the paper conveyance path forms a smooth curve with an outward convex shape. Because of the continuous shape, the paper 522 always receives the force in the direction of the arrow L which bends outward. Therefore, the paper 522 is constantly pressed against the outer paper guide,
The paper feed roller 22 runs idle. Therefore, the paper jam does not occur even if the paper 522 is significantly over-conveyed. As a result, it is possible to realize a paper feeding unit having a simple structure without requiring a precise control device for accurately controlling the paper conveyance amount and avoiding excessive conveyance.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image recording apparatus according to the present invention will be described in detail with reference to FIGS. FIG. 1 is a side sectional view showing a configuration of an embodiment in which the image recording apparatus of the present invention is applied to a facsimile, and FIG. 2 is an enlarged side sectional view showing a sheet feeding section of the image recording apparatus of FIG. FIG. 3 is a perspective view showing an example of the configuration of the one-way power transmission means arranged in the paper feed roller portion of the image recording apparatus of FIG.

First, the overall structure of the facsimile will be described with reference to FIG. Paper cassette 5 that constitutes the paper storage unit
1, 52 are housed in the image recording apparatus main body 8. Of these, the lower paper cassette 52 is the image recording apparatus main body 8
It may be removable from. That is, the facsimile is the image recording apparatus main body 8 having only the upper cassette 51.
On the other hand, it is possible to make the lower cassette section 52 optional and to divide it.

In the paper cassettes 51 and 52, the paper 51
1, 512 are stored. The paper 511 is separated and conveyed by the paper feed roller 21 of the upper cassette 51, and the paper 512 is separated and conveyed by the paper feed roller 22 of the lower cassette 52. The separated and conveyed sheets are skew-corrected by the registration rollers 71 and 72. Incidentally. 61, 62,
Reference numerals 63, 67, 68, and 69 are paper guides.

Although not shown in detail, the scanning optical system 81 comprises a laser diode, a polygon mirror, an F-θ lens and the like. The laser light emitted from the scanning optical system 81 forms an electrostatic latent image on the surface of the photosensitive drum 82 according to the image signal to be recorded. The developing device 88 has a toner accumulating portion for accommodating toner therein, a developing roller, and the like, and develops the electrostatic latent image on the photosensitive drum 82 with toner. A high voltage of about −700 V is applied to the transfer roller 83 by a high voltage circuit (not shown), and due to the action of this static electricity,
The toner image on the photosensitive drum 82 is transferred onto a sheet. Cleaning blade 8 made of elastic material such as urethane rubber
In No. 5, the toner remaining on the photosensitive drum 82 without being transferred to the paper is scraped off and cleaned. The scraped toner is stored in the waste toner box 86. Charger 8
Reference numeral 4 denotes, for example, a scorotron charger, which charges the surface of the cleaned photosensitive drum 82 uniformly again. The heat fixing device 87 applies heat to the sheet having the toner image transferred on its surface to fix the image, thereby forming a permanent image.

The transmission originals accumulated on the tray 91 are separated one by one by the separation rollers 92 and 93, and are guided by the guide 9
4 and 95, and the paper guide 9 by the discharge roller 98.
The paper is ejected from 6,97. The light emitted from the light source (not shown) and reflected by the transmission original is reflected by the mirrors 101, 102, 10
It is reflected by 3 and guided to the reader 100. The reading device 100 converts the image information of the transmission document into an electric signal. The converted image information is transmitted to the communication partner via a telephone line or the like and recorded by the image recording device of the communication partner.

Next, referring to FIG. 2, the structure of the paper feeding section of the recording apparatus of FIG. 1 will be described. Paper feed roller 2 of upper cassette 51
1 rotates in the direction of arrow A and separates and conveys a sheet. The paper feed roller 22 of the lower cassette 52 rotates in the direction of arrow B to separate and convey the paper. The stepping motor 4 can rotate bidirectionally in the arrow C and D directions. A timing pulley 32 is arranged on the same axis as the stepping motor 4. A timing pulley 34 is arranged on the same axis as the paper feed roller 21. Timing belt 3
3 is a drive force of the stepping motor 4 for the paper feed roller 2
Tell 1. The timing pulley 32, the timing belt 33, and the timing pulley 34 form power transmission means for the upper cassette 51. The paper feed roller 21 is coaxially arranged with the one-way power transmission means 11.

The construction of the one-way power transmission means 11 coaxial with the paper feed roller 21 will be described with reference to FIG. The shaft 41 of the paper feed roller 21 is inserted into the one-way power transmission means, that is, the one-way clutch 11. The one-way power transmission means 11 is press-fitted into the timing pulley 34.
The one-way power transmission means 11 transmits the rotational driving force in the direction of the arrow A to the paper feeding roller 21, but does not transmit the rotational driving force in the opposite direction to the paper feeding roller 21. Therefore, the rotational driving force in the arrow A direction transmitted to the timing pulley 34 is transmitted to the sheet feeding roller 21, but the opposite driving force in the arrow G direction is not transmitted to the sheet feeding roller 21.

Referring again to FIG. 2, the structure of the paper feeding section will be described. The gear 31 arranged on the same axis as the stepping motor 4 and the gear 35 meshing with the gear 31 reverses the rotation direction of the driving force of the stepping motor 4 and transmits it to the sheet feeding roller 22 of the lower cassette. The timing pulley 36 arranged on the same axis as the gear 35 rotates the timing pulley 38 by the timing belt 37. Since the timing pulley 38 is arranged on the same axis as the paper feed roller 22, the driving force transmitted by the gear 35 causes the paper feed roller 22 to rotate in the direction opposite to the stepping motor 4. In this way, the gear 31, the gear 35, the timing pulley 36, the timing belt 3
7. The timing pulley 38 forms the power transmission means of the lower cassette 52. The shaft of the paper feed roller 22 is inserted in the one-way power transmission means, that is, the one-way clutch 12. The one-way power transmission means 12 is press fitted into the timing pulley 38. One-way power transmission means 12
Transmits the rotational driving force in the direction of arrow B to the paper feed roller 22, but does not transmit the rotational driving force in the opposite direction to the paper feed roller 22. Therefore, the timing pulley 38
The rotational drive force in the direction of arrow B transmitted to the paper feed roller 2
2, but the driving force in the opposite arrow F direction is not transmitted to the paper feed roller 22.

The registration rollers 71 and 72 correct the skew of the sheet and feed the sheet. Paper guides 61, 62, 63, 6
Reference numerals 4, 65, 66, 67, 68 guide the sheets separated and conveyed by the sheet feeding rollers. Of these, the outer peripheral side paper guide 6
The inner surfaces of the reference numerals 1, 62 and 63 have a shape in which gentle curved lines are formed so as to be convex outward. Also, the paper guide 6
2, 63 can be opened up to the position shown by the chain double-dashed line in the figure, and even if a paper jam occurs, the paper can be taken out easily.

The transmission operation of the facsimile having such a configuration will be described. When a transmission document is placed on the tray 91, a controller (not shown) receives a signal from a transmission document sensor (not shown) and starts the transmission procedure. When the transmission is enabled, the separation rollers 92 and 93 start to rotate, and the transmission originals are separated and conveyed one by one. The paper to send is the paper guide 9
Light is emitted from a light source (not shown) in the transport path composed of 4, 95. The light reflected on the surface of the transmitted document is reflected by the mirror 1.
The optical path is turned back by 01, 102, 103, and the light is directed to the reading device 100, converted into an electric signal, and transmitted. The transmission original is conveyed while being read, and is ejected by a paper ejection roller 98 to a transmission original tray (not shown).

Next, the recording operation of the facsimile will be described. When a controller (not shown) receives a facsimile signal, the controller starts warming up the fixing device 87 and rotates the polygon mirror of the scanning optical system 81. When the fixing device 87 and the scanning optical system 81 become operable, the paper feeding operation is started.

The paper feeding operation will be described with reference to FIG. For example, when it is desired to feed the paper 522 in the lower cassette 52, the stepping motor 4 rotates in the direction of arrow D according to a command from a controller (not shown). This rotational driving force is transmitted to the gear 35 through the gear 31, the rotation direction is reversed in the arrow E direction, and the timing pulley 36, the timing belt 37, and the timing pulley 38 cause the one-way power transmission means 12 to the arrow B direction. Is transmitted as the rotational driving force of. The one-way power transmission means 12 transmits the rotational driving force in the arrow B direction to the paper feed roller 22. Therefore, the paper feed roller 22 separates and conveys the paper 522. The paper 522 separated from the paper cassette 52 is rotated by the paper feed roller 22, and the paper guides 61, 62, 63, 64, 65,
The sheet is conveyed in a conveying path formed by 66 and heads to the registration rollers 71 and 72 of the skewed sheet correcting unit. The sheet is further conveyed in the conveying path and reaches the sheet sensor 73. A controller (not shown) takes in the signal from the paper sensor 73, drives the stepping motor 4 for a certain period of time, and stops it. In the meantime, the sheet hits the contact portion of the stopped registration rollers 71 and 72 and is further conveyed,
Skew is corrected. After that, the registration rollers 71 and 72 start to rotate and convey the paper along the paper guides 67 and 68.

According to the present invention, when the paper is fed from the lower cassette 52 where a jam is likely to occur due to excessive conveyance of the paper, the inner side surfaces of the paper guides 62 and 63 on the outer peripheral side of the conveyance path form a gentle curve which is convex outward. Since the sheet has a curved shape, the sheet is always pressed against the inner surfaces of the sheet guides 62 and 63 on the outer peripheral side, and the sheet feeding roller 22 idles. Therefore, the paper jam does not occur even if the paper is excessively conveyed. For this reason, it is not necessary to accurately control the carry amount by the paper feed roller 22, and the paper feed device can be configured with a simple mechanism. The rotation of the stepping motor 4 in the arrow D direction is transmitted to the one-way power transmission means 11 as rotation in the arrow G direction via the timing pulley 32, the timing belt 33, and the timing pulley 34. However, the one-way power transmission means 1
1 transmits the rotational driving force in the arrow A direction to the sheet feeding roller 21, but does not transmit the driving force in the opposite direction, the arrow G direction, to the sheet feeding roller 21. That is, the paper feed roller 21 does not rotate, and the paper is never separated and conveyed from the upper cassette 51.

On the other hand, when paper is fed from the upper cassette 51, the stepping motor 4 rotates in the direction of arrow C according to a command from a controller (not shown). This rotational driving force is transmitted to the one-way power transmission means 11 and 12 via the respective power transmission means. At this time, the rotational drive force in the direction of arrow A is transmitted to the one-way power transmission unit 11, and the rotational drive force in the direction of arrow F is transmitted to the one-way power transmission unit 12. Therefore, the paper feed roller 21 is driven, but the paper feed roller 22 is not driven, and the paper 5 in the upper cassette 51 is
Only 11 is separated and conveyed. With such a simple mechanism, 2
Paper can be selectively fed from one cassette.

Charger 8 to which a high voltage of several kV is applied
Ions generated from 4 uniformly charge the surface of the photosensitive drum. The scanning optical system 81 that has received the image signal indicates the arrow N
A latent image corresponding to an image signal is written by a laser beam on the photoconductor drum rotating in the direction. The latent image on the photosensitive drum is
The toner is developed by the developing device 88 to form a visible image. At this time, the sheet conveyed at a predetermined timing reaches the contact portion between the photosensitive drum and the transfer roller. The high voltage applied to the transfer roller 83 causes the toner image on the photosensitive drum to be transferred onto the paper. The toner remaining on the photosensitive drum without being transferred onto the paper is scraped off by the cleaning blade 85, and the waste toner box 86 is discharged.
It is stored inside. Further, the sheet on which the image of the toner is transferred on the surface is guided to the sheet guide 69 and heads to the fixing device 87. The image of the sheet is fixed by the heat of the fixing device 87, and the sheet is ejected to the outside of the machine to complete the recording operation.

In the above embodiment, the combination of the timing pulley and the timing belt is used as the power transmission means, but they may be replaced by a gear train. When this gear train is used, there is an advantage that the driving force transmission means can be connected more easily than a timing belt or the like, especially when the lower cassette is a removable type.

Further, in the above embodiment, only the case of the image recording apparatus having the two-stage paper cassette has been described. Similar effects can be obtained with the fourth-stage paper cassette.

[0038]

According to the present invention, the driving force from one rotational driving force generating source is transmitted to a plurality of paper feed rollers via the power transmission means for reversing the rotation direction, and the respective paper feed rollers are also supplied. Further, since the unidirectional power transmission means that operates in the opposite direction is provided, it is possible to selectively feed paper from a plurality of paper storage units with a simple configuration.

Further, since the inner side surface of the paper guide on the outer peripheral side of the conveying path has a shape in which gentle curves which are convex outward are connected, even when the paper is fed from the paper storing section having a long conveying path, Paper can be fed stably without causing jams.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a configuration of an embodiment in which an image recording apparatus of the present invention is applied to a facsimile.

FIG. 2 is an enlarged side sectional view showing a paper feeding unit of the image recording apparatus of FIG.

3 is a perspective view showing an example of a configuration of a one-way power transmission means arranged in a paper feed roller portion of the image recording apparatus of FIG.

FIG. 4 is a side cross-sectional view showing a linear transport path in a paper feed section of a conventional image recording apparatus.

FIG. 5 is a side view showing a behavior of a sheet in a sheet feeding section of a conventional image recording apparatus.

FIG. 6 is a side view showing the behavior of the paper in the paper supply unit of the image recording apparatus of the present invention.

[Explanation of symbols]

4 Rotational driving force generating means (stepping motor) capable of rotating bidirectionally 8 Image recording apparatus main body 11 1-direction power transmission means 12 1-direction power transmission means 21 Paper feed roller of upper sheet cassette 51 22 Lower sheet cassette 52 Paper feed rollers 31, 35 Rotation direction reversing gears 32, 34, 36, 38 Timing pulleys 33, 37 Timing belts 51 Upper paper cassette 52 Lower paper cassettes 511, 512 Paper 61, 62, 63, 64, 65, 66, 67,68,6
9 Paper guide 71 Paper skew correction member (registration roller) 72 Paper skew correction member (registration roller) 81 Scanning optical system 82 Photoconductor drum 83 Transfer roller 84 Charging device 85 Cleaning blade 86 Waste toner box 87 Thermal fixing device 88 Development Device 91 Document tray 92, 93 Separation roller 94, 95, 96, 97 Paper guide 98 Paper ejection roller 100 Reading device 101, 102, 103 Mirror

Claims (13)

[Claims] 1. A plurality of paper storage units, each of which is configured to rotate a paper feed roller arranged in a predetermined direction to selectively separate and convey the paper from one of the paper storage units. In an image recording apparatus for recording an image on a sheet, bidirectionally rotatable driving force generating means, and driving force from the driving force generating means disposed between the driving force generating means and the paper feeding roller A plurality of power transmission means for transmitting to the respective paper feed rollers in opposite rotation directions, and a plurality of power transmission means arranged respectively between the power transmission means and the paper feed roller to rotate the paper feed roller only in the predetermined direction. An image recording apparatus comprising: a directional power transmission means. 2. A plurality of paper accommodating portions, each of which is arranged to rotate in a predetermined direction to selectively separate and convey the paper from one of the paper accommodating portions. In an image recording apparatus for recording an image on a sheet, bidirectionally rotatable driving force generating means, and the feeding force generating means and the paper feeding roller are respectively arranged in the predetermined direction. The one-way power transmission means for rotating only the one-way power transmission means and the one-way power transmission means, which are arranged between the one-way power transmission means and the sheet feeding roller, transmit the driving force from the driving force generation means to the respective sheet feeding rollers in opposite rotation directions. An image recording apparatus comprising a plurality of power transmission means. 3. The image recording apparatus according to claim 1 or 2, wherein the plurality of sheet storage units include a pair of odd-numbered and even-numbered sheet cassettes. 4. The image recording apparatus according to claim 1, wherein the plurality of power transmission means includes a pair of gears, and one power transmission means is an odd number than the other power transmission means. An image recording apparatus having a large number of gears. 5. The image recording apparatus according to claim 1, wherein the one-way power transmission means is a one-way clutch. 6. The image recording apparatus according to claim 1, wherein the bidirectionally rotatable driving force generating means is a stepping motor. 7. A printer including the image recording device according to claim 1 as a recording unit for recording an image to be printed. 8. A facsimile including the image recording apparatus according to claim 1 as a medical image recording means. 9. A copying machine including the image recording apparatus according to claim 1 as a document image recording unit. 10. A paper storage unit mounted on the main body of the image recording apparatus and a paper storage unit detachable from the main body, wherein paper feed rollers arranged in the respective paper storage units are rotated in a predetermined direction. In an image recording apparatus that selectively separates and conveys a sheet from one of the sheet storage units and records an image on the sheet, a driving force generating unit mounted on the main body and a sheet feeding unit of the removable sheet storage unit. A power transmission unit that is arranged between the roller and a driving force generation unit and that transmits the driving force from the driving force generation unit to the paper feeding roller in a direction opposite to that of the paper feeding roller on the main body side; and the power transmission unit and the paper feeding roller. And a one-way power transmission means for rotating the paper feed roller only in the predetermined direction, and a detachable paper storage device. 11. A paper storage unit mounted on a main body of an image recording apparatus and a paper storage unit detachable from the main body, wherein paper feed rollers arranged in the respective paper storage units are rotated in a predetermined direction. In an image recording apparatus that selectively separates and conveys a sheet from one of the sheet storage units and records an image on the sheet, a driving force generating unit mounted on the main body and a sheet feeding unit of the removable sheet storage unit. A one-way power transmission unit that is arranged between the one-way power transmission unit and the paper feed roller and that is disposed between the one-way power transmission unit and the paper feed roller. A detachable paper storage device, comprising: a power transmission means for transmitting a driving force to the paper feed roller in a direction opposite to that of the paper feed roller on the main body side. 12. The sheet storage device according to claim 10 or 11, wherein the plurality of sheet storage units include a pair of odd-numbered stage and even-stage sheet cassettes. 13. A plurality of paper storage units, a paper skew correction unit that corrects skew of paper, and a paper guide that guides paper from the plurality of paper storage units to the paper skew unit, each of which is provided. The paper feed roller disposed in the paper storage unit of the above is rotated in a predetermined direction to selectively separate and convey the paper from one of the paper storage units, and the paper is substantially inverted along the paper guide, and then the paper skew is set. In an image recording apparatus that corrects skew feeding of a sheet by a line correction unit and feeds the image to record an image on the sheet, a paper guide on an outer peripheral side of a conveyance path from a lower sheet storage unit to the skew feeding correction unit. The image recording apparatus is characterized in that the inner shape thereof is formed into a shape in which convex smooth curves are connected to the outer peripheral side.