JP2001088964A - Sheet feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate various kinds of sheets differed in property from thin paper to thick paper by use of the same device by spraying air to float the sheets. SOLUTION: This feeder comprises a sheet housing means 1 for housing sheets P, a sheet supplying means 2 for supplying the sheets P from the sheet housing means 1, and an air spraying means 4 having a nozzle 3 opened opposite to the end surface of the sheets P housed in the sheet housing means 1 to spray air through the nozzle 3. The air spraying means 4 is constituted so that the nozzle 3 having different opening forms 5, 6 is selectable or replaceable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus for feeding stacked sheets, and more particularly to a sheet feeding apparatus for separating and feeding sheets having high adhesion between sheets.

[0002]

2. Description of the Related Art In image forming apparatuses such as printers and copiers, cut sheets that enable continuous paper feeding are generally used as a medium on which an image is formed. , Plain paper and high-quality paper specified by the copier manufacturer were used. Since these sheets have low surface smoothness, the sheet-to-sheet adhesion is low, and even when the sheets are fed one by one from a sheet stacking unit such as a sheet feed tray, a multi-feed in which a plurality of sheets are fed in close contact with each other. Was relatively easy to prevent. However, in recent years, with the diversification of recording media, transport of various types of sheets, including those with high surface smoothness, has been required, and in particular, whiteness has increased with the development of color technology. In addition to coated paper, OHP sheets, tracing paper, etc., which have been made glossy, there is an increasing demand for the same model to transport especially thick paper having a high basis weight. This coated paper, OHP sheet, tracing paper and the like have a strong adhesion between the sheets, so that it is difficult to prevent double feeding, and special measures are required for sheet supply.

For example, the coated paper will be described as an example. As the quality of the coated paper increases, the amount of coating increases and the white gloss, which is an optical property, increases. The degree increases. On the other hand, when the surface smoothness increases, the gap between the papers when they come into contact with each other becomes narrower, the air pressure does not pass through the gap, and the generated negative pressure is maintained, and the adhesion between the sheets (between the papers) is reduced. Become stronger. In particular, when a smooth sheet such as a coated paper is stacked in a high humidity environment, the sheets adhere to each other and the degree of adhesion is further increased. OH
P-sheets and the like also have high surface smoothness and high sheet-to-sheet adhesion.

[0004] When feeding out such smooth sheets having strong adhesion between sheets one by one from a sheet feeding tray on which the sheets are stacked, the sheets are separated one by one using a normal plain paper feeding apparatus. It becomes very difficult to transport. In particular, a sheet feeding device using a draw-in roll that rotates by contacting the surface of the sheet with a predetermined pressing force to draw the sheet, and a method in which a supply roll and a separation roll are pressed and separated at a constant pressure when the sheet is separated. In this case, when the smooth sheet is separated and conveyed, the pressing force is required to be about 30 times as large as that of the ordinary plain paper. As a method of eliminating such close contact with a smooth sheet in advance, the present applicant has disclosed Japanese Patent Application Laid-Open No. H11-5643.
Discloses a technique for blowing air from the side of a stacked sheet. According to such a technique, a great effect can be achieved in eliminating the adhesion force in the smooth sheet.

[0005]

As described above, the technique of feeding air after blowing air from the side of the paper to release the close contact makes it possible to remarkably improve the transport performance of the smooth sheet. The problem is that the ease with which the sheet floats and the ease with which the sheet is separated is not uniform depending on the type of sheet. That is, the sheet conveying device using the air blowing means is characterized in that the sheets are lifted and the close contact between the sheets is released.However, the ease of floating the sheets and the ease of separating the sheets are determined by the close contact between the sheets. It is determined by the degree and rigidity. For example, taking the case of thin paper and thick paper as an example, thin paper is easily levitated by air but difficult to separate, while thick paper is difficult to levitate but is easy to separate if it floats. As described above, it has been difficult to separate and float various types of sheets, such as thin paper to thick paper, by blowing air using the same apparatus.

Further, as a result of repeated studies by the present inventors, it has been discovered that the state of floating and separation of sheets differs depending on the environmental conditions in which the conveyed sheets are stored. For example, at a temperature of 28 ° C. and a humidity of 85%, 10 to 30 N is required to loosen the adhered sheet,
At a temperature of 20 ° C. and a humidity of 55% and a temperature of 10 ° C. and a humidity of 15%, it was possible to loosen at 5 to 10N. The result is
The same is true even when the temperature is increased.It is clear that the sheet adhesion is weak under low humidity and low humidity, and it is clear that the sheet adhesion is high under high humidity, and it has been found that humidity has a large effect on the sheet adhesion I came to.

[0007]

In order to solve the above-mentioned technical problems, a sheet feeding apparatus according to the present invention comprises a sheet feeding device shown in FIG.
(b) ((b) is a cross-sectional view taken along line AA of (a)), as shown in FIG. A nozzle 3 opened to face the end face of the sheet P accommodated in the sheet accommodating means 1, and an air blowing means 4 for blowing air from the nozzle 3; It is characterized in that the nozzle 3 having the opening shapes 5 and 6 can be selected or replaced.

The air blowing means 4 is configured so that the nozzles 3 having different opening widths can be selected or replaced according to the type of the sheet P. It is preferable because it is possible to select appropriate opening shapes 5 and 6 according to the degree of adhesion between the sheets and the sheet rigidity, and it is possible to obtain an appropriate air volume distribution.

In particular, the nozzle 3 of the air blowing means 4 is characterized in that the opening width of the upper portion of the thick sheet P is narrowed, and is indicated by reference numeral 5 in FIG. If such an opening shape is selected, the rigidity is high and it is difficult to levitate. On the other hand, for a thick sheet P in which levitation is performed one by one, a sufficient air volume for levitating is given, and The air volume can be adjusted to be small for the sheet P, and the sheet can be stably supplied to the thick sheet P.

As a selection of the nozzle 3, FIG.
As shown by arrow Q in (b), it can be configured to be switchable up and down by using a power source such as a solenoid (not shown) according to the type of the sheet, and the sheet feeding device can be provided without a special power source. Can be switched up and down or the like by a user who uses. Furthermore, if the user and the service technician of the apparatus can appropriately perform the replacement of the nozzle 3, the stable sheet supply can be performed when the paper type to be mainly used is determined by the user. This is preferable in that

Further, the apparatus further comprises designation means for enabling the user of the sheet feeding apparatus to designate the type of the sheet P, and selecting the nozzle 3 based on the designation result by the designation means. If it is a feature, there is no need to provide a special mechanism for recognizing the type of the sheet P, and it is possible to select an optimal nozzle shape based on a user's selection. As the specification means, for example, a button provided on a control panel of the apparatus main body corresponds, and as the type of the specified sheet P, if the basis weight of the sheet P can be specified, the thickness of the sheet P can be easily specified. It is possible to do.

Further, the air blowing means 4 can select or replace the nozzles 3 having different opening shapes 5 and 6 according to the humidity conditions in the environment where the sheets P stored in the sheet storing means 1 are stored. With such a configuration, it is possible to select an optimal opening shape in accordance with the degree of adhesion between the sheets P due to a difference in humidity, which is preferable in that the sheet P handling performance can be further improved. here,
As means for making the nozzle 3 selectable or replaceable, for example, a method of automatically switching based on humidity recognition by a humidity sensor, a method of previously replacing the nozzle 3 based on environmental conditions in which the apparatus is constantly used, and the like can be mentioned.

From the viewpoint of reducing the space for switching the opening shape of the nozzle 3 in the air blowing means 4, the air blowing means 4 includes the nozzle 3 in which a plurality of opening members having different opening shapes are arranged in a stack. It is preferable that the shape of the opening of the nozzle 3 be changed by changing the positional relationship between the plurality of opening members. In this embodiment, the form of the opening member may be appropriately selected from a block, a plate, and the like, and the number of the opening members may be two or more. Further, if the opening region of the nozzle 3 composed of a plurality of overlappingly arranged opening members is a closed opening, the opening itself of each opening member is not limited to a hole but also includes a notch. Furthermore, as for the plurality of opening members, at least one opening member may be configured to be movable so that the position of the opening member is changed.

Next, the operation of the above technical means will be described. Air blowing means 4 for blowing air from the side surface of the sheet P stacked on the sheet storage means 1 is provided.
Have different opening shapes 5, 6 as shown in FIG.
Is provided. The nozzle 3 is configured to be switchable, and when the user of the apparatus recognizes the type of the sheet P loaded in the sheet storage unit 1, for example, the thickness of the sheet P, an optimal opening shape is selected according to the thickness of the sheet P and the like. Can be switched by selecting. For example, when the sheet P has a large basis weight and is a thick sheet, an opening shape such as reference numeral 5 in FIG. Here, as a feature of a thick sheet, while a sufficient lift is required to lift the sheet P, the lifted sheet P is in a state of being separated almost every sheet, and thereafter, a strong lift is unnecessary. Become. Therefore, when an opening shape such as reference numeral 5 is selected, the opening is narrowed toward the upper portion, so that the flow velocity is increased as a whole, and in a portion with a wide opening width, a sufficient opening is sufficient. Lift will act.
On the other hand, at the lifted position, the tip of the opening becomes narrower, and the lift is reduced. By this air action, even a thick sheet can be appropriately separated and supplied.

On the other hand, as a feature of the thin sheet, it is easy to lift up from the stacked state, but a plurality of sheets P are floated at the same time, and in this state, the plurality of sheets P are not separated yet. There are cases. Therefore, an extremely strong lift is not required, but a constant lift is required even in a floating state. Therefore, when thin sheets are stacked, the opening shape has a constant width as shown in FIG.
It is configured such that an opening shape such as reference numeral 6 can be selected. When an opening shape such as reference numeral 6 is selected, a predetermined lift acts in the floating state even in a thin sheet in which two or more sheets are still bundled in a floating state.
Further, the sheets can be separated one by one, and as a result, even a thin sheet can be appropriately separated and supplied.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings. FIG. 2 shows an embodiment of an image forming apparatus to which the present invention is applied. In the figure,
The image forming apparatus 21 as a sheet feeding apparatus includes an image reading apparatus (IIT) 23 for reading a document image and a receiving unit 29 connected to an external device 25 such as a personal computer (PC) via a communication line 27. , The image writing device 31 based on the image information from the receiving unit 29.
Is provided with an image recording control section 33 for controlling the image recording. The image recording control unit 33 controls the image writing device 31,
The control of the sheet supply unit 60 described later and the control of another sheet conveyance system are also executed. The image forming apparatus 21 has an image carrier 35 on which an electrostatic latent image is written by the image writing device 31, and is disposed along the circumferential direction of the image carrier 35 to charge the image carrier 35. And a developing device 39 for developing the charged image carrier 35 using toner, and transfers the toner image on the image carrier 35 to the sheet conveyed by the transfer roller 43. ing. Furthermore,
A fixing device 45 for fixing the image transferred to the sheet,
A discharge roller 47 for discharging the fixed sheet, a discharge tray 49 for stacking the sheet discharged by the discharge roller 47, and a cleaner 41 for collecting the remaining toner not used for the transfer are provided.

Further, the image forming apparatus 21 is provided with a plurality (four in the present embodiment) of sheet supply trays 59 for storing sheets by size or sheet feeding direction, and these sheets are provided in upper and lower stages. The sheet supply tray 59 is configured such that a bottom plate (not shown) provided therein is moved up and down by driving a motor (not shown). A sheet supply unit 60 is provided above the sheet supply tray 59, and separates and conveys the sheet by contacting the upper surface of the sheet lifted by the bottom plate. The sheet is conveyed to an image forming unit including the carrier 35 and the like. Further, each sheet supply tray 59 is provided with an air blowing device 71 for blowing air so as to face the side surface of the sheet.

FIG. 3 is a perspective view showing the sheet supply section 60. The sheet supply unit 60 has a draw-in roll that frictionally contacts the upper surface of the stacked sheets P and sequentially feeds out the sheets P.
(Pickup roll) 61, a conveying roll (feed roll) 62 that separates the sheet P fed from the drawing roll 61 and conveys the sheet P toward the downstream portion, and separates the sheets P one by one while being pressed by the conveying roll 62. A separating roll (retard roll) 63 is provided. In the present embodiment, the pull-in roll 61, the transport roll 62, and the separating roll 63 are formed of rolls having the same shape and the same size as each other, and perform the transport operation of the sheet P by frictionally contacting the sheet P. It is configured as follows.

The transport roll 62 is driven by receiving power from a feed motor (not shown) via a drive gear and a feed clutch (not shown). On the other hand, the draw-in roll 61 is configured to rotate around an axis 62 a of the transport roll 62 via an arm 81, and is rotated by gears 82 in conjunction with driving of the transport roll 62. Further, the pull-in roll 61 falls on the upper surface of the sheet P via the link 84 by the operation of the solenoid 83 which operates in response to a drive signal from the image recording control unit 33, and rotates with a predetermined pressing force. By driving, the sheet P can be fed out. Also, the arm 81
Is detected by the photo sensor 85, and when a predetermined number of sheets P are conveyed and the upper surface of the sheets P is lowered, the bottom plate in the sheet supply tray 59 is raised, and The height is configured to be within a certain range.

The draw-in roll 61 in the present embodiment is
The sheet P is transported to the downstream transport roll 62 and the separation roll 63.
The sheet P is conveyed to the nip portion of
It is comprised so that it may be separated from. If the sheet P is pressed against the sheet P even after the pull-in operation is completed, the sheet P rotates with the pressure even when the rotation is turned off, and a conveying force is applied to the second and subsequent sheets P, resulting in excessive supply. Causes double feed. Therefore, when the sheet P is not supplied and the sheet is not fed, the pull-in roll 61 is once pulled up and separated from the upper surface of the sheet. Further, the separating roll 63 is brought into contact with the transport roll 62 with a small pressure by a spring 89 via a support 88 about a pivot 87 as a rotation center. Further, the separating roll 63 is connected to a first gear 91 and a fixed second gear 92 via a torque limiter 90. Here, when the separating roll 63 rotates with the transport roll 62, the sliding torque of the torque limiter 90 is transmitted to the first gear 91 via the retard shaft 63a, and the first gear 91 tries to rotate clockwise. Since the second gear 92 is fixed, the first gear 91 operates to ride on the second gear 92, and as a result, the retard pressure, which is the pressure on the transport roll 62, is increased.

FIG. 4 is a plan view of the sheet supply tray 59. An end guide 65 for regulating the rear end face of the sheet P in the sheet feeding direction is provided upstream of the sheet supply tray 59 in the sheet feeding direction.
Is provided, and a side fixed guide 67 is provided on a side surface in a direction perpendicular to the sheet feeding direction, and a movable side guide 6 configured to be movable depending on the size of the sheet P is provided at a position facing the fixed guide 67.
9 are provided. An air blowing device 71 is provided near the side fixed guide 67, and is configured to blow air to the sheet P via a nozzle 73 provided in the side fixed guide 67. The air blowing device 71 is provided with a FAN that rotates in the direction of the arrow in the figure, and is configured to supply high-pressure air via a duct 72.

FIG. 5 is a schematic explanatory view showing the sheet supply tray 59 from the side. As described above, the drawing roll 61 in the sheet supply unit 60 is connected to the sheet supply tray 59.
In contact with the upper surface of the sheets P stacked on the sheet P, and acts to sequentially feed out the sheets P. Further, the sheet P fed out from the pull-in roll 61 passes through a separating section constituted by the transport roll 62 and the separating roll 63, and the sheet P
Even if more than one sheet is fed out, they are conveyed to the downstream side in a state where they are separated one by one. In the case of transporting ordinary plain paper or copy paper, the contact pressure of the draw-in roll 61 on the upper surface of the paper is set to about 100 gf, and the retard pressure between the transport roll 62 and the separating roll 63 is set to 4 g during transport.
It is set to be about 00 gf.

Coated paper having a high sheet-to-paper adhesion strength in such a setting state (a composite sheet in which a coating color, which is a kind of paint, is applied to both sides or one side of the sheet P for the purpose of improving printability) or When a thick paper or the like having a high basis weight is to be conveyed, a plurality of sheets P are conveyed collectively, and are conveyed to the downstream side as a double feed. At this time, the experiment by the inventor found that simply trying to separate coated paper or cardboard by simply increasing the contact pressure would require an extremely high contact pressure with respect to the contact pressure with general plain paper and copy paper. It became clear. Therefore, in the present embodiment, an air blowing device 71 is provided as one of means for eliminating adhesion to a sheet P having high adhesion such as coated paper, and in order to improve the supply performance of thick paper, a high-pressure air is provided. Is sprayed on the sheet P, thereby eliminating the close contact of the sheet P and enabling the supply of the sheet P without increasing the contact pressure of each roll.

Here, the air blowing device 71 shown in FIG.
A nozzle 73, which will be described in detail later, is provided at the air outlet of the duct 72, so that the lower end of the opening is below the uppermost sheet P loaded, and the upper end of the opening is above the uppermost sheet P. Is configured. For example, by intermittently blowing air from the nozzle 73, a lift as shown by an arrow in FIG.
The sheets P are separated one by one. By driving the draw-in roll 61 in this state, the sheet P is fed out approximately one by one, and is conveyed downstream in a stable state.

FIGS. 6A and 6B are explanatory diagrams for explaining the opening shape of the nozzle 73 in the present embodiment.
In this embodiment, the nozzle 73 has an opening 101 for thick paper and an opening 102 for thin paper. The opening 101 for thick paper and the opening 102 for thin paper have a width of about 40 mm and a height of about 40 mm. It is constituted by 20 mm. These openings are configured to be selectable by the user, and more specifically, the nozzle 73 can slide up and down,
A fixed side such as a leaf spring structure (not shown) and a positioning structure such as a latch member (not shown) can be used to stop at the position where the slide is moved up and down. It is configured so that it can be positioned and fixed to the guide 67. Here, when the sheet P is recognized as a thin paper having a basis weight of, for example, 120 gsm or less, the user pulls the nozzle 73 in the arrow Q1 direction shown in FIG. Approximately the center of the opening 102 for use. At this time, the duct 72 of the air blowing device 71 shown in FIG. 4 is configured such that its air blowing port is substantially at the height of the center of the upper surface on which the sheets P are stacked. Is blown out from the opening 102 for thin paper, and no air is blown out from the opening 101 for thick paper.

The air blown out from the thin paper opening 102 causes the stacked sheets P to float. As described above, the standard position on the upper surface of the sheet P coincides with the approximate center height of the opening 102 for thin paper having a height of about 20 mm. Will rise. Since this sheet P is thin paper, it is highly likely that two or more sheets P will rise as a bundle, and it is necessary to further apply a lift even when the sheet P rises about 10 mm to the upper side of the opening. The opening 102 for thin paper in the present embodiment has a substantially rectangular shape, and the same air as in the central portion of the opening is blown near the upper side of the opening. As a result, the sheet P, which has risen as a bundle to the vicinity of the upper side of the opening, maintains the necessary lift even at the upper side of the opening, and can further obtain a separating action by blowing air. As a result, the sheets P made of thin paper that have risen as a bundle are handled one by one near the upper side of the opening, and are supplied to the downstream side in a stable state.

Next, the sheet P has a basis weight of about 200 gs, for example.
m is recognized as a thick paper of about m
The nozzle 73 is pushed down in the direction of the arrow Q2 shown in FIG. At this time, as described above, the duct 72 of the air blowing device 71 shown in FIG. 4 is configured such that the air blowing port thereof is substantially at the height of the center of the loading surface of the sheets P, and as a result, The air from the blowing device 71 is blown out from the opening 101 for thick paper, and the air is not blown out from the opening 102 for thin paper.

The air blown out from the cardboard opening 101 causes the stacked sheets P to float. As described above, the standard position on the upper surface of the sheet P coincides with the approximate center height of the cardboard opening 101 having a height of about 20 mm. Will rise. Since the sheet P is a thick paper, a stronger lift is required to float the sheet P as compared with the thin paper. In the present embodiment, the opening 1 for cardboard is used.
01 is configured such that the opening width becomes narrower toward the upper end thereof, and the opening 1 for thin paper is reduced by the reduced thickness.
The overall opening area is smaller than that of No. 02. As a result, the flow velocity of the air is increased and the lift is increased. In general, for a sheet P made of cardboard, a strong lift is required to lift the sheet P, but the raised sheet P is unlikely to rise as a bundle, and
It is in a state of being sorted for each sheet. Therefore, a strong lift is not required when the sheet P has risen to the vicinity of the upper end of the opening. Opening 1 for cardboard in the present embodiment
In No. 01, since the upper end of the opening is configured to become gradually narrower, the lift gradually becomes weaker as it rises, and the lifted sheet P is not given more lift than necessary. As a result, stable supply of thick paper with a large basis weight is possible.

In the above description, the nozzle shape is simply changed depending on whether the sheet P is thin paper or thick paper.
In addition to these conditions, it is also possible to configure so as to change the shape of the nozzle based on environmental conditions such as humidity, which has a strong influence on the degree of adhesion. According to the research conducted by the present inventors, it is necessary that the temperature of 28 ° C., which is the first zone, and the humidity of 85% require 10 to 30 N to loosen the sheet P, whereas the temperature of 20 ° C. which is the second zone This is because it has become clear that the separation can be performed at 5 to 10 N at a humidity of 55% and a temperature of 10 ° C. and a humidity of 15%, which is the third zone.
In response to this result, a more detailed experiment was conducted. As a result, the adhesion between the sheets was extremely high when the humidity was 60% or more, with little influence on the temperature conditions, especially for coated paper as the type of sheet P. When the humidity was high and the humidity was 60% or less, the adhesion between the sheets was weak. This tendency is the same for cardboard, and even cardboard is likely to float in a low-humidity environment. Therefore, when a normal sheet P is conveyed, the thin paper opening 102 shown in FIG. 6 is used to feed thick paper under high humidity or to feed coated paper under high humidity. Is selected, nozzles having different opening shapes and opening widths can be selected according to the type of the sheet P, and the sheet P can be stably fed regardless of the type. It becomes possible.

FIGS. 7A and 7B show the nozzle 7 shown in FIG.
The opening shape of No. 3 is changed. Reference numeral 103 shown in FIG. 7A is an opening for cardboard, which forms a triangle that is convex upward. Due to this triangular shape, similarly to the opening 101 for the thick paper shown in FIG. 6B, the opening width becomes narrower toward the upper end thereof, and the entire width becomes smaller than that of the opening 102 for the thin paper. The opening area is small.
As a result, the flow velocity of the air is increased and the lift is increased. Further, since the upper end of the opening is configured to be gradually narrowed, the lift is gradually reduced as the ascending is performed, and the lifted sheet P is not given an unnecessarily large lift. As a result, stable supply of thick paper with a large basis weight is possible. By adopting the opening 103 for the thick paper, the entire opening area becomes smaller than that of the opening 101 for the thick paper shown in FIG. It is possible to obtain a stronger lift on the upper surface.

In FIG. 7B, the opening of the nozzle 73 is changed from the thin paper opening 102 of FIG. 7A to a thin paper opening 10 of a triangular shape having a downward convex shape.
4 are provided. The air is blown out from the downwardly convex triangular opening, so that the lift acts as the sheet P rises. That is, when the sheet P reaches the vicinity of the upper side of the thin paper opening 104, which is the upper side of the triangular opening, the sheet P is subjected to the largest lift, and for example, initially, the sheet P overlaps with the thin basis paper having a low basis weight. Even in this state, the sheet is further separated one by one by the large lift in the vicinity of the upper side of the thin paper opening 104. As a result, double feeding is prevented even for thin paper, and stable paper feeding is enabled.

As described above, according to the present embodiment, the nozzle 73 depends on the type of the sheet P, particularly, the basis weight of the sheet P.
By switching the opening shape of the
Can be supplied stably.

In the above description, the configuration for enabling the user of the image forming apparatus 21 to pull or press the nozzle has been described as switching the opening shape of the nozzle 73. , Can be automatically switched. For example, a solenoid (not shown) is connected to the upper end or lower end of the nozzle 73 via a link (not shown) or the like, and is switched up and down based on the instruction of the image recording control unit 33 described in FIG. It is. More specifically, a displacement sensor (not shown) for detecting, for example, the thickness of the sheet P is provided at a predetermined position of the sheet conveying unit 51 shown in FIG.
Upon receiving the output from the displacement sensor, the image recording control unit 33
The solenoid may be operated in accordance with the instruction from. It is possible to measure the thickness of the sheet P almost accurately by the displacement amount output from the displacement sensor. Based on the measured result, when the sheet P is thick, the nozzle 73 is set to the opening 101 for the thick paper, 103, nozzle 73 when thin
Is switched to the openings 102 and 104 for thin paper.
With this configuration, it is possible to recognize the thickness of the sheet in approximately one sheet conveyance and switch the opening shape of the nozzle 73 automatically, so that different types of sheets are not confused by the user. The sheet P can be stably conveyed.

Further, for example, a nozzle 73 using a solenoid
May be switched by pressing a grammage selection button (not shown) provided on a control panel (not shown) of the image forming apparatus 21, for example. That is, the user of the image forming apparatus 21 is configured to be able to select the basis weight according to the type of the sheet P, and based on an instruction of the image recording control unit 33 that recognizes the user's selection,
When thick paper is formed by a solenoid or the like, the opening 101 for the thick paper,
At the time of thin paper, the nozzle 73 is connected to the opening 10 for thin paper.
It switches to 2,104. With this configuration, the user can omit the operation of actually moving the nozzle 73 up and down, and can stably convey different types of sheets P by a simple operation of specifying the type of the sheet P. . The selection means for selecting the type of the sheet P provided on the control panel is not limited to the selection of the basis weight, and may be a type for selecting the type of the sheet such as a coated paper. It is also possible to configure so that humidity information in an environment where the forming apparatus 21 is installed can be input.

Second Embodiment In the first embodiment, the nozzle 73 is provided with the opening 101 or 103 for the thick paper and the opening 102 or 104 for the thin paper, and these can be switched manually or automatically. In this embodiment, instead of switching, the sheet P
Are configured to be exchangeable according to the type of the device. The same components as those in the first embodiment are described in the first embodiment.
The same reference numerals are given, and the detailed description is omitted here.

FIGS. 8 (a), 8 (b) and 8 (c) show a state in which the thick paper nozzle has been replaced. The nozzle 105 shown in FIG. 8A has a pentagonal opening in which the opening width is gradually narrowed toward the upper end portion of the rectangular opening. The nozzle 106 shown in FIG. 8B has a triangular opening that is convex upward, and the nozzle 107 shown in FIG. 8C has a stepwise (two-stage) opening width. Has a convex opening with a narrow upper opening width. These nozzles 105, 106, and 107 are formed of a thin plate having a thickness of about 0.5 mm, and the opening thereof has a height of about 20 mm and a maximum width of about 40 mm. In the present embodiment, these nozzles 105, 106, and 107 are configured to be fixed by, for example, a leaf spring structure (not shown) provided on the side fixed guide 67 shown in FIG. When fixed to the side fixed guide 67, it is connected to the duct 72 of the air blowing device 71, and the nozzles 105, 106, 10
It is configured such that air can be blown out from the opening 7.

These nozzles 105, 106, 107
Is configured as a cardboard nozzle such that the opening width decreases toward the upper end thereof. Therefore, as described above, a strong lift is given by the high flow velocity on the upper surface of the stacked sheets P, and the lift is suppressed near the upper end. As a result, it is difficult to cause the sheet P to float, and when the sheet P rises, it becomes possible to supply the sheet P in a stable state to the thick paper that has been separated one by one.

FIGS. 9 (a), 9 (b) and 9 (c) show a state where the thin paper nozzles have been replaced. The nozzle 108 shown in FIG. 9A has a pentagonal opening in which the opening width is gradually narrowed toward the lower end of the rectangular opening. The nozzle 109 shown in FIG. 9B has a downwardly convex triangular opening, and the nozzle 110 shown in FIG. 9C has a stepwise (two-step) opening width. And the opening of the lower part has a narrow inverted convex shape. Similarly, these nozzles 108, 109, and 110 are each formed of a thin plate having a thickness of about 0.5 mm.
The maximum width is about 40 mm, and it is configured to be fixed to the side fixed guide 67 by a leaf spring structure (not shown) or the like, and is further connected to the duct 72 of the air blowing device 71 to blow air from the opening. It is configured so that it is possible.

These nozzles 108, 109, 110
The thin paper nozzle has a wide opening width even at the upper end thereof as a thin paper nozzle.
In the same manner as described above, consideration is taken so that the sheet P that has floated can be further separated one by one. Here, the nozzles 108, 109, and 110 according to the present embodiment have a smaller opening area than the thin-paper opening 102 having a simple rectangular shape, so that a high flow velocity can be obtained. Even for the same thin paper, it is possible to select an appropriate nozzle according to the difference in basis weight and the type of sheet such as tracing paper. Further, the nozzle can be arbitrarily selected based on the humidity condition in the environment where the image forming apparatus 21 is installed.

Third Embodiment FIG. 10 shows an embodiment of a sheet feeding unit (sheet feeding device) that realizes a small space for switching the opening shape of the nozzle 73 in the air blowing device 71. still,
FIG. 10A is a cross-sectional explanatory view in which the air blowing device 71 of the sheet supply unit is cut in the vertical direction, and FIG.
It is a sectional view taken along the line BB. In the figure, the sheet supply unit is provided with a sheet supply tray 59 as in the first and second embodiments.
Is provided with an air blowing device 71 at the side thereof, and a nozzle 73 is provided at an air blowing port of a duct 72 of the air blowing device 71. The configuration of the nozzle 73 is different from the first and second embodiments. .

That is, in the present embodiment, the nozzle 73 is provided with two plates 201 and 20 having different opening shapes.
2 in a superposed arrangement. Here, the plate 201 is fixed to the duct 72 of the air blowing device 71. On the other hand, the plate 202 is attached to a lever 203 provided above the air blowing device 71 by an elastic member 2 such as a film.
The plate 201 is connected so as to slide on the surface of the plate 201 by operating the lever 203. The plate 202 is provided with the spring 20.
5, since it is always urged downward, it slides stably in conjunction with the operation of the lever 203. The lever 203 has a latch structure, and is held at two positions.

Further, in this embodiment, the plate 201
11A is, for example, a rectangular shape having a width of about 40 mm and a height of about 20 mm, as shown in FIG. 11A, while the opening shape of the plate 202 is, for example, FIG.
As shown in the figure, it has the same width dimension as the opening of the plate 201, but the upper end of the opening is formed in a triangular shape that protrudes upward, and is configured to become gradually narrower upward,
Further, the lower edge of the opening is cut out at the same width as the opening of the plate 201.

Further, the operation of the lever 203 is not limited to manual operation, but is automatically performed using a solenoid, a motor, or the like based on information obtained by information obtaining means such as a sheet type and environmental conditions. It is also possible.

Next, the operation of the sheet supply unit according to the present embodiment will be described. Now, when switching the opening shape of the nozzle 73 according to the type of sheet, environmental conditions, and the like,
The lever 203 may be moved to or. At this time, when the lever 203 is set to the position of, the plates 201 and 202 are overlapped and arranged as shown in FIG. Used as a nozzle 73. On the other hand, when the lever 203 is set to the position of, since the plates 201 and 202 are overlapped and arranged as shown in FIG. 12B, the opening shape of the nozzle 73 is such that the upper end of the opening is gradually narrowed. Used as a nozzle 73 for thin paper. In order to switch the opening shape of the nozzle 73, it is sufficient that there is a vertical space equal to or less than two openings of the nozzle 73. For example, in the case of the nozzle 73 shown in FIG. In addition, since the vertical size of the space for three openings of the nozzle 73 is required, a space for switching the opening shape of the nozzle 73 can be realized in a small space.

Further, if a latch structure that can hold the position of the lever 203 at three or more positions is used, the opening shape of the nozzle 73 that can be switched can be set to three or more. Further, in a mode in which the nozzles 73 are provided at a plurality of locations and all of them need to be set to the same setting, from the viewpoint of effectively preventing the setting error of the opening shape of the nozzle 73, the respective levers are connected. It is preferable that each lever be operated simultaneously by one operation.

[0046]

As described above, according to the present invention,
When the sheets are separated using the air blowing means, the opening shape can be selected and exchanged according to the type of the sheets, so that a wider range of sheets can be supplied stably.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory diagrams showing an outline of a sheet feeding apparatus according to the present invention.

FIG. 2 is an explanatory diagram illustrating an outline of an image forming apparatus according to an embodiment.

FIG. 3 is a perspective view illustrating a sheet supply unit according to the embodiment.

FIG. 4 is a plan view of a sheet supply tray according to the embodiment.

FIG. 5 is a schematic explanatory view showing a sheet supply tray in the present embodiment from the side.

FIGS. 6A and 6B are explanatory diagrams for explaining the opening shape of a nozzle in the present embodiment.

FIGS. 7A and 7B are explanatory diagrams for explaining the opening shape of another nozzle in the present embodiment.

FIGS. 8A, 8B, and 8C are explanatory diagrams illustrating a state in which a thick paper nozzle according to the second embodiment is replaced. FIG.

FIGS. 9A, 9B, and 9C are explanatory diagrams showing a state in which a thin paper nozzle according to the second embodiment is replaced. FIG.

FIG. 10A is an explanatory diagram illustrating an outline of a sheet supply unit according to a third embodiment, and FIG. 10B is a cross-sectional view taken along line BB in FIG.

FIGS. 11A and 11B are explanatory views showing a structure of two plates constituting a nozzle. FIGS.

FIGS. 12A and 12B are explanatory diagrams showing a change in the opening shape of a nozzle.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sheet accommodating means, 2 ... Sheet supply means, 3 ... Nozzle, 4 ... Air blowing means, 5, 6 ... Opening shape, 21
... image forming apparatus, 31 ... image writing apparatus, 33 ... image recording control section, 35 ... image carrier, 37 ... charger, 39 ... developing apparatus, 43 ... transfer roller, 45 ... fixing apparatus, 59 ... sheet supply tray , 60: sheet supply unit, 61: pull-in roll,
62: transport roll, 63: separating roll, 65: end guide, 67: side fixed guide, 69: side movable guide, 71: air blowing device, 72: duct, 73: nozzle, 101: opening for thick paper, 102 ... opening for thin paper, 1
03: opening for thick paper, 104: opening for thin paper, 105,
106, 107, 108, 109, 110 ... nozzle, 2
01, 202: plate, 203: lever, 204: elastic member, 205: spring, P: seat.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroaki Fujikura 2274 Hongo, Ebina-shi, Kanagawa Prefecture F-Xerox Co., Ltd. F-term (reference) 3F343 FA02 FB02 FB04 FC01 JB12 JB13 JD28 KB05 KB20 LA03 LB08 LC19 MA05 MA47 MB04 MB14

Claims (6)

[Claims] A sheet storage unit configured to store a sheet, a sheet supply unit configured to supply a sheet from the sheet storage unit, and a nozzle opened to face an end surface of the sheet stored in the sheet storage unit. And an air blowing means for blowing air from the nozzle, wherein the air blowing means is configured to be able to select or replace a nozzle having a different opening shape. 2. The sheet feeding device according to claim 1, wherein the air blowing unit is configured to be able to select or replace a nozzle having a different opening width according to a type of the sheet. 3. The sheet feeding apparatus according to claim 1, wherein the nozzle in the air blowing means is configured such that an opening width at an upper portion of the thick sheet is narrowed. 4. The apparatus according to claim 1, further comprising a designation unit configured to allow a user of the sheet feeding device to designate a sheet type, wherein the nozzle is selected based on a designation result by the designation unit. The sheet supply device according to claim 1, wherein: 5. The air blowing means is configured to be capable of selecting or replacing a nozzle having a different opening shape in accordance with a humidity condition in an environment in which sheets stored in the sheet storing means are stored. The sheet feeding device according to claim 1, wherein: 6. The air blowing means includes a nozzle in which a plurality of opening members having different opening shapes are overlapped and arranged, and changes the positional relationship between the plurality of opening members to change the opening shape of the nozzle. The sheet feeding device according to claim 1, wherein: