JP2004123316A - Paper feed mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent generation of wrinkles by disposing a guide member to reduce a space in a printing medium carrying route in the printing medium carrying route between a paper feed roller and a printing medium carrying roller to remove waviness generated in the printing medium. <P>SOLUTION: A paper feed mechanism comprises a fixed guide member disposed on a printing medium between a paper feed roller 14 and a printing medium carrying roller and a movable guide member urged in a direction for reducing a space from the fixed guide in which the printing medium passes therethrough. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a paper feed mechanism.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a printing apparatus such as a printer, a paper feed roller around which a rubber roller is wound and a friction piece (brake shoe) are attached as a paper feed mechanism for feeding a print medium as paper from a paper cassette or a paper tray. A friction separation method is generally used in which the printing medium is separated one by one while the printing medium is separated by pressing the separated separation pieces into pressure and rotating the paper feeding roller.
[0003]
FIG. 2 is a diagram showing a printing apparatus provided with a conventional multi-purpose tray.
[0004]
In the figure, reference numeral 100 denotes a printing apparatus as an image forming apparatus, and 101 denotes a multi-purpose tray. The multi-purpose tray 101 forms a straight-path paper feed route in order to reduce the load on a print medium in order to cope with the feeding of special paper such as thick paper or thin paper.
[0005]
When the print medium is conveyed, the print medium is stacked on the multi-purpose tray 101 and conveyed while being separated by the paper feed roller and the separation piece. Thereafter, the registration roller corrects the paper skew. At the same time, the paper is conveyed into the printing apparatus 100.
[0006]
In this type of printing apparatus 100, in order to reduce the size of the entire apparatus, a registration roller is provided without placing a great distance from a paper feed roller.
[0007]
[Patent Document 1]
JP-A-6-166458
[0008]
[Problems to be solved by the invention]
However, in a paper feed system using a paper feed roller and a separation piece, like the paper feed mechanism of the conventional printing apparatus 100, stable performance can be obtained with a relatively small number of parts and an inexpensive structure. On the other hand, when the print medium is fed, there is a drawback that the print medium undulates on both sides of the paper feed roller, and paper feed wrinkles (wrinkles) easily occur particularly at the leading end of the print medium.
[0009]
Such undulation of the print medium that occurs on both sides of the paper feed roller causes the print medium to be transferred to a print medium transport roller such as a registration roller that is arranged to transport the print medium next to the paper feed roller. When it is bitten, it is wrinkled by being pinched and crushed by the rollers. Then, in the printing apparatus 100 such as an electrophotographic printer, a wrinkled portion appears in an image as a printing defect.
[0010]
However, if the print medium transport route is curved after passing through the paper feed roller, and if a sufficient distance is provided between the paper feed roller and the print medium transport roller disposed next to the print medium, the print medium is not printed. While the wrinkles are likely to be stretched before reaching the medium transport roller, in this case, the entire printing apparatus 100 becomes large. If the paper feed roller and the registration roller are arranged close to each other in order to reduce the size of the printing apparatus 100, especially when thin paper is fed in a high-temperature and high-humidity environment, the thin paper as a print medium is used. In many cases, a certain amount of undulation is generated from the beginning, and the frequency of wrinkles increases.
[0011]
Also, in order to remove waviness generated in the print medium and prevent wrinkles from occurring, a technique of spreading the print medium outward with a roller having a large-diameter portion and a small-diameter portion between a paper feed roller and a registration roller is known. It has been proposed (for example, see Patent Document 1). However, when trying to reduce the size of the printing apparatus 100, the distance between the sheet feeding roller and the registration roller becomes shorter, so that it becomes impossible to provide a roller having the large diameter portion and the small diameter portion. When a roller having the large-diameter portion and the small-diameter portion is provided, it is not necessary to dispose a registration roller at a downstream side of the registration roller with a conveyance distance long enough to extend the undulation of the print medium. Therefore, the size of the printing apparatus 100 is increased. Further, a roller having a large-diameter portion and a small-diameter portion may be used instead of the registration roller. However, in this case, it is not possible to reliably correct the skew of the print medium.
[0012]
The present invention solves the problem of the conventional paper feed mechanism, and includes a guide member for narrowing a gap (gap) of the print medium transport route in a print medium transport route between a paper feed roller and a print medium transport roller. It is an object of the present invention to provide a paper feeding mechanism that can prevent the generation of wrinkles by removing the wavy generated on a print medium by disposing the paper feeding mechanism.
[0013]
[Means for Solving the Problems]
Therefore, in the paper feed mechanism of the present invention, the gap between the fixed guide member disposed on the print medium transport route between the paper feed roller and the print medium transport roller and the fixed guide through which the print medium passes is provided. And a movable guide member urged in a direction to narrow the distance.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a first perspective view showing the configuration of the main part of the paper feeding mechanism according to the first embodiment of the present invention, and FIG. 3 is the configuration of the main part of the paper feeding mechanism according to the first embodiment of the present invention. FIG. 4 is a diagram showing a cassette sheet feeding route according to the first embodiment of the present invention, and FIG. 5 is a diagram for mounting a wrinkle removing guide according to the first embodiment of the present invention. FIG. 6 is an exploded view of a main part showing a configuration, and FIG. 6 is a diagram showing a configuration of a wrinkle removing roller and a wrinkle removing disk in the first embodiment of the present invention.
[0016]
In FIG. 1, reference numeral 11 denotes a front cover of a printing apparatus as an image forming apparatus, which forms a lower side of a paper guide of a multi-purpose tray, and a separation piece 12 urged by a spring (not shown) can swing on a rotation fulcrum. Attached to. Reference numeral 13 denotes a top guide as a fixed guide member that forms the upper side of the paper guide of the multi-purpose tray, and is capable of rotating a paper feed roller shaft 15 on which a paper feed roller 14 is mounted and a wrinkle removing roller 16 as a rotation guide member. Holding. Reference numeral 17 denotes a wrinkle removing disk serving as a rotation guide member which is disposed at a position symmetrical to the wrinkle removing roller 16 with respect to the paper feed roller shaft 15 and has the same outer diameter.
[0017]
In the present embodiment, the printing apparatus has a configuration similar to that of the printing apparatus 100 described in “Prior Art”, and is adapted to feed special paper such as thick paper or thin paper as a print medium. It is desirable to have a multi-purpose tray for the operation. Further, the printing device is an electrophotographic printer, an ink jet printer, an ink ribbon printer, etc., but may be any type of printing device, or a facsimile device, an image forming device other than a printing device such as a copying machine. There may be.
[0018]
FIG. 3 shows a side of the front cover 11 opposite to the side shown in FIG. In FIG. 3, reference numeral 18 denotes a wrinkle removing guide as a movable guide member, which is made of a material having high sliding (sliding) mobility, such as polyacetal resin (POM), and is disposed at a position which is symmetrical with respect to the paper feed roller 14. And is swingably mounted on a rotation fulcrum of the front cover 11. Reference numeral 19 denotes a registration roller, and reference numeral 20 denotes a pressure roller which is urged by a spring (not shown) and pressed against the registration roller 19. Here, the registration roller 19 and the pressure roller 20 function as a pair of print medium conveyance rollers, and the leading end of the print medium fed by the paper feed roller 14 is engaged with the engagement portion of the registration roller 19 and the pressure roller 20. The skew of the print medium is corrected by the butting.
[0019]
In FIG. 3, the exposed curved surface of the wrinkle removing guide 18 also forms a sheet conveying surface of a cassette sheet feeding route disposed below the printing apparatus. Here, a description will be given of a cassette sheet feeding route for feeding a print medium stored in a sheet feeding cassette disposed below the printing apparatus.
[0020]
In FIG. 4, 21 is a paper feed roller, and 22 is a separation piece. Then, the printing media stacked and stored in a cassette (not shown) disposed below the printing apparatus are separated and conveyed one by one by the feed roller 21 and the separating piece 22. Reference numeral 23a denotes a registration roller, and 23b denotes a pressure roller which is urged by a spring (not shown) and pressed against the registration roller 23a, and constitutes a first registration roller pair 23 in a cassette sheet feeding route. In this case, the registration roller 19 and the pressure roller 20 form a second registration roller pair.
[0021]
In this case, the print medium conveyed by the paper feed roller 21 is abutted against the first registration roller pair 23 to correct the skew, and then conveyed downstream by the first registration roller pair 23. The conveyed print medium is conveyed between a registration roller 19 as a second registration roller pair and a pressure roller 20 along a guide 24, and further, by the registration roller 19 and the pressure roller 20, the printing device is moved. The sheet is conveyed to an internal image recording unit (not shown).
[0022]
FIG. 5 is an exploded view showing how the wrinkle removing guide 18 is attached to the front cover 11. A coil spring 26 as a position regulating means is sandwiched between the wrinkle removing guide 18 and the front cover 11. The tip of the wrinkle removing guide 18 is attached so as to urge it in the direction indicated by the arrow A in FIG. 5 (upward in the figure).
[0023]
As shown in FIG. 6, the wrinkle removing disk 17 is formed integrally with the shaft 17a and rotates integrally with the paper feed roller 14. The wrinkle removing roller 16 is independent of the shaft 17a and thus rotates independently.
[0024]
The waviness generated on the print medium by the paper feed roller 14 is removed to some extent by the wrinkle removing roller 16 and the wrinkle removing disk 17, but is not completely removed. However, in the print medium transport route between the wrinkle removal guide 18 and the paper supply roller 14, the print medium is substantially S-shaped (the wrinkle removal guide 18 is connected to the print medium more than the position where the paper supply roller 14 contacts the print medium). The contact position is at the upper side), whereby the print medium is stretched in the width direction. Then, in the print medium that has passed through the wrinkle removal guide 18, the waving is completely removed. In the present embodiment, the paper feed mechanism has a top guide 13, a wrinkle removal guide 18, a registration roller 19, a pressure roller 20, and the like.
[0025]
Next, the operation of the sheet feeding mechanism having the above configuration will be described. First, a case where thin paper is used as a print medium will be described.
[0026]
FIG. 7 is a sectional view of a main part of the paper feeding mechanism according to the first embodiment of the present invention.
[0027]
First, as shown in FIG. 7, the print medium is fed in the direction indicated by arrow C. In this case, since the wrinkle removing guide 18 is urged by the coil spring 26 in the direction shown by the arrow B, the leading end of the print medium which is separated and conveyed one by one by the feed roller 14 and the separation piece 12 is conveyed. Is fed between the wrinkle removal guide 18 and the top guide 13. Since the print medium is flattened by being sandwiched between the wrinkle removing guide 18 and the top guide 13, the print medium is engaged with the first registration roller pair 23 in a state where the wavy generated on the print medium is removed. Be included. Therefore, wrinkles do not occur on the print medium.
[0028]
Then, the print medium is abutted against the first pair of registration rollers 23 to correct the skew. Subsequently, the print medium is transported by the registration roller 19 and the pusher roller 20. At this time, the driving force applied to the paper feed roller 14 is turned off.
[0029]
Next, a case where thick paper is used as a print medium will be described.
[0030]
In this case, since the printing medium is thick paper, the stiffness is stronger than that of thin paper. Therefore, as shown in FIG. 7, when the print medium is fed in the direction indicated by the arrow C, the wrinkle removing guide 18 is urged by the coil spring 26 in the direction indicated by the arrow B. The print medium is pressed down to the position shown by the wavy line. Then, the print medium is directly bitten by the first registration roller pair 23. Therefore, wrinkles do not occur on the print medium. In this case, since the print medium is made of thick paper and has a strong stiffness, no waving occurs. Then, the print medium is abutted against the first pair of registration rollers 23 to correct the skew. Subsequently, the print medium is transported by the registration roller 19 and the pusher roller 20. At this time, the driving force applied to the paper feed roller 14 is turned off.
[0031]
Next, results of an experiment performed using an actual print medium will be described. Here, the effect of the urging force for urging the wrinkle removing guide 18 in the direction indicated by the arrow B and the size of the gap between the wrinkle removing guide 18 and the top guide 13 on the effect of preventing the generation of wrinkles will be described. .
[0032]
FIG. 8 is a table showing the urging force and the occurrence of wrinkles in the first embodiment of the present invention, and FIG. 9 is a table showing the dimensions of the gap and the occurrence of wrinkles in the first embodiment of the present invention. .
[0033]
First, in FIG. 7, the effect of the magnitude of the urging force for urging the wrinkle removal guide 18 in the direction indicated by the arrow B on the effect of preventing wrinkles generated on the print medium is described using thin paper and thick paper as print media. An experiment was performed for the case where the above was done. The results of the experiment were summarized in the table shown in FIG.
[0034]
In the table shown in FIG. 8, the urging force is the magnitude of the urging force for urging the wrinkle removing guide 18 in the direction indicated by the arrow B in FIG. 7. The case where it did not perform was evaluated as ○.
[0035]
Further, the thin paper and the thick paper used in the experiment are media having a thickness usable as a printing medium, and the thin paper has a thickness of 0.07 [mm], and the thick paper has a thickness of 0.24 [mm]. One used. Note that the urging force 0 [g] is a result of an experiment performed with the wrinkle removal guide 18 removed. As a result of the experiment, as shown in FIG. 8, no wrinkling was observed on the thick paper even when the biasing force was changed from 0 [g] to 20 [g]. However, with respect to thin paper, wrinkles were observed at an urging force of 15 g or more or at an urging force of 1 g or less.
[0036]
When the print medium is thin paper, wrinkles with an urging force of 1 [g] or less occur because the wrinkles generated when the print medium is separated by the paper feed roller 14 and the separation piece 12 are not removed by the wrinkle removal guide 18. It is considered to be. In addition, the generation of wrinkles with an urging force of 15 [g] or more occurs because the urging force of the wrinkle removing guide 18 is too strong when the print medium is conveyed by the registration roller 19 and the pressure roller 20, and thus the registration rollers 19 and It is considered that the print medium is pulled by the pressure roller 20 and the wrinkle removing guide 18, and a new wrinkle is generated.
[0037]
From the results of the above experiment, it is understood that the appropriate urging force of the wrinkle removing guide 18 is 2 g to 10 g.
[0038]
Next, an experiment was conducted on the effect of the size of the gap between the wrinkle removal guide 18 and the top guide 13 on the effect of preventing wrinkles generated on the print medium when thin paper and thick paper were used as the print medium. The results of the experiment were summarized in the table shown in FIG. The experiment was performed with the urging force for urging the wrinkle removing guide 18 in the direction indicated by the arrow B in FIG. 7 at 2 g, 5 g, and 10 g.
[0039]
In the table shown in FIG. 9, a case where wrinkles did not occur with all the urging forces was marked with “○”, and a case where wrinkles occurred with any of the urging forces was marked with “x”. Further, the thin paper and the thick paper used in the experiment are media having a thickness usable as a printing medium, and the thin paper has a thickness of 0.07 [mm], and the thick paper has a thickness of 0.24 [mm]. One used.
[0040]
As a result of the experiment, as shown in FIG. 9, no wrinkles were generated for the thick paper, and wrinkles were generated for the thin paper when the gap was separated by 0.6 mm or more. That is, when the printing medium is thin paper, when the gap is 0.6 [mm], the wrinkle removing guide 18 has no effect. Further, from the experimental results, it can be seen that the gap may be 0 [mm], that is, the wrinkle removal guide 18 may be in contact with the top guide 13. Therefore, it is understood that it is not necessary to finely adjust the gap between the wrinkle removing guide 18 and the top guide 13, and the number of steps of the adjusting operation can be reduced.
[0041]
Further, the thickness of the thin paper is 0.07 [mm], and even when the thickness is smaller than the dimension of the gap, wrinkles are not generated if the thickness is within the range of 0.5 [mm]. It is believed that this was prevented for the following reasons.
[0042]
That is, the undulation that occurs when the print medium is separated by the feed roller 14 and the separation piece 12 is a large undulation in the width direction of the print medium. The large undulation of the print medium is suppressed by the wrinkle removal guide 18 and the top guide 13. In addition, the print medium after passing through the wrinkle removing guide 18 has an effect of returning to a flat (tan) shape, and wrinkles do not occur when the print medium is conveyed by the registration roller 19 and the pusher roller 20. Therefore, it is considered that the size of the gap between the wrinkle removing guide 18 and the top guide 13 may be larger than the thickness of the thin paper, as long as the size is within a range that can suppress the wavy of the greatly wavy print medium. Can be
[0043]
From the results of the above experiments, it is understood that the gap between the wrinkle removal guide 18 and the top guide 13 is appropriately from 0 [mm] to 0.5 [mm].
[0044]
As described above, in the present embodiment, the top guide 13 as the fixed guide member is provided on the print medium transport route between the paper feed roller 14 and the registration roller 19 as the print medium transport roller and the pusher roller 20. The wrinkle removal guide 18 as a movable guide member is urged in a direction to narrow a gap with the top guide 13 through which a print medium passes. Therefore, when thin paper is fed as a print medium, the undulation of the print medium generated at the time of feeding is sandwiched between the wrinkle removal guide 18 and the top guide 13 forming the upper side of the paper guide, thereby flattening the undulation and printing. It is possible to effectively prevent paper feed wrinkles from occurring on the medium.
[0045]
Further, when thick paper is fed as a print medium, since the print medium itself is stronger than the load received from the wrinkle removal guide 18, the print medium easily pushes down the wrinkle removal guide 18 to the registration roller 19. The leading edge of the print medium can be reached. For this reason, paper feed jam does not occur due to the load that the print medium receives from the paper transport route as the print media transport route.
[0046]
Therefore, even in a straight path structure having poor conditions for preventing wrinkles generated on a print medium when thin paper is fed, and in a structure in which the distance between the paper feed roller and the print medium transport roller is not sufficiently long, the thin paper can be used. , Thick paper, and a special medium can be stably fed.
[0047]
It is also conceivable to prevent the occurrence of paper feed wrinkles by regulating the paper transport route using a film.However, the means for regulating the paper transport route using a film is a film tension due to aging or environmental change. Changes. On the other hand, in the present embodiment, since the sheet conveyance route is regulated by the solid wrinkle removing guide 18 and the coil spring 26, there is no fear of a change in tension due to a change over time or an environmental change.
[0048]
Further, since the wrinkle removing guide 18 can be used as a left and right common member, it also contributes to an improvement in assembly workability.
[0049]
Next, a second embodiment of the present invention will be described. The components having the same configuration and the same operation as those of the first embodiment are given the same reference numerals, and the description thereof is omitted.
[0050]
FIG. 10 is a first perspective view of a wrinkle removing guide according to a second embodiment of the present invention, FIG. 11 is a second perspective view of a wrinkle removing guide according to a second embodiment of the present invention, and FIG. FIG. 11 is a detailed view of a roller of a wrinkle removing guide according to a second embodiment of the present invention, and is an enlarged view of a portion D in FIG. 10, and FIG. It is a table.
[0051]
In FIG. 10, a small-diameter roller 21 is rotatably mounted at the tip of the wrinkle removing guide 18. FIG. 11 shows a side of the wrinkle removing guide 18 opposite to the side shown in FIG. The wrinkle removing guide 18 is formed in a guide shape at a portion indicated by E in FIGS. 10 and 11 so that the leading end of the print medium does not hit the antinode of the roller 21 during paper feeding. The other configuration is the same as that of the first embodiment, and the description is omitted.
[0052]
As shown in FIG. 12, the roller 21 has a protrusion 21a, which engages with the fixing portion 18a of the wrinkle removing guide 18 and rotatably supports the roller 21. In FIG. 12, reference numeral 27 denotes a path through which the print medium passes. The hatching portion 18b provided on the wrinkle removing guide 18 is provided with an inclination so that the roller 21 does not strike when the print medium is conveyed. The surface of the end portion 18c of the wrinkle removal guide 18 shown in FIGS. 10 and 11 facing the print medium is lower than the surface of the roller 21 facing the print medium.
[0053]
The operation of the sheet feeding mechanism according to the present embodiment is the same as that of the first embodiment, and a description thereof will be omitted.
[0054]
Also in the present embodiment, as in the first embodiment, the magnitude of the urging force for urging the wrinkle removing guide 18 in the direction indicated by the arrow B in FIG. Regarding the effect on the effect of prevention, an experiment was performed in the case where thin paper and thick paper were used as print media. And the result of the experiment was put together as a table shown in FIG. In the table shown in FIG. 13, the urging force is the magnitude of the urging force for urging the wrinkle removing guide 18 in the direction indicated by the arrow B in FIG. 7. The case where it did not perform was evaluated as ○.
[0055]
As can be seen from the table shown in FIG. 13, in this embodiment, no wrinkling was observed even with an urging force 1.5 times that in the first embodiment.
[0056]
As described above, in the present embodiment, by disposing the roller 21 at the tip end of the wrinkle removing guide 18, the load on the print medium from the sheet transport route can be further reduced. Therefore, it is possible to prevent paper feed wrinkles from occurring when thin paper is fed as a print medium, and to achieve smoother paper feed operation when feeding thick paper as a print medium.
[0057]
Further, since the load applied to the print medium from the paper transport route by the wrinkle removal roller 16 is reduced, the tension of the wrinkle removal guide 18 is increased, and the occurrence of paper feed wrinkles when feeding thin paper as the print medium is more ensured. Can be prevented.
[0058]
Next, a third embodiment of the present invention will be described. The components having the same configuration as those of the first and second embodiments and the same operations are denoted by the same reference numerals and description thereof will be omitted.
[0059]
FIG. 14 is a sectional view of a main part of a sheet feeding mechanism according to the third embodiment of the present invention.
[0060]
In the present embodiment, as shown in FIG. 14, the sheet feeding mechanism includes a plunger 22 in addition to the coil spring 26 as a position regulating unit of the wrinkle removing guide 18. The plunger 22 is connected to the wrinkle removing guide 18 by a connecting member 22a. The plunger 22 is connected to a drive source (not shown) and a control unit for controlling the drive source. The control unit drives the drive source based on the thickness of the print medium, and operates the plunger 22 in the direction indicated by the arrow H.
[0061]
When the plunger 22 is turned off, the wrinkle removing guide 18 is urged by the tension of the coil spring 26 so that the tip moves in the direction indicated by the arrow F. Further, when the plunger 22 is on, when the force of the plunger 22 overcomes the tension of the coil spring 26 and the connecting member 22a is sucked in the direction indicated by the arrow H, the wrinkle removing guide linked to the plunger 22 is provided. The tip of 18 moves in the direction indicated by arrow I, and the gap between wrinkle removal guide 18 and top guide 13 increases.
[0062]
Next, the operation of the sheet feeding mechanism according to the present embodiment will be described.
[0063]
First, when a user performs thin paper setting on a printer driver and sends it to the printing apparatus as a command before print data, a control unit (not shown) in the printing apparatus analyzes the command and prints a print medium to be printed according to the command. Is thin paper or thick paper. Then, the control unit issues an instruction to a drive source that drives the plunger 22 based on the determination of either thin paper or thick paper. At this time, when the print medium is thin paper, the control unit issues an instruction to the drive source to turn off the plunger 22. When the print medium is thick paper, the control unit turns on the plunger 22. To the drive source to
[0064]
When the plunger 22 is off, the wrinkle removing guide 18 is urged by the tension of the coil spring 26 in the direction indicated by the arrow F. When the print medium is fed in the direction indicated by arrow G, the wrinkle removal guide 18 is urged by the coil spring 26 in the direction indicated by arrow F, so that the leading end of the print medium is The undulation of the print medium generated at the time of sheet feeding by being sandwiched between the first registration roller pair 23 and the top guide 13 is flattened.
[0065]
When the plunger 22 is on, the plunger 22 is sucked in the direction indicated by the arrow H, and widens the gap between the wrinkle removing guide 18 and the top guide 13. As described above in the first embodiment, the gap may be set to be larger than 0.24 [mm], which is the thickness of the print medium usable in the printing apparatus. In addition, it is desirable to open the opening by 0.5 mm or more in consideration of manufacturing variations of the print medium. And, as described above, in the case of thick paper, wrinkles hardly occur. Therefore, in the case of thick paper, even if the gap between the wrinkle removal guide 18 and the top guide 13 is widened, it hardly affects the prevention of wrinkles.
[0066]
As described above, in the first embodiment, since the tension is always applied to the wrinkle removing guide 18 by the coil spring 26 although it is small, in the case of thick paper, the print medium receives a load from the paper transport route. However, in the present embodiment, when the user sets thick paper, the plunger 22 is operated to positively widen the paper route, thereby reducing the load on the print medium from the paper transport route. For this reason, it is possible to prevent the occurrence of wrinkles when feeding thin paper as a print medium, and to achieve stable paper feed when feeding thick paper as a print medium.
[0067]
Next, a fourth embodiment of the present invention will be described. The components having the same configuration as those of the first to third embodiments and the same operations are denoted by the same reference numerals, and description thereof is omitted.
[0068]
FIG. 15 is a front view of a wrinkle removing roller according to the fourth embodiment of the present invention, FIG. 16 is a perspective view of the wrinkle removing roller according to the fourth embodiment of the present invention, and FIG. 17 is a fourth embodiment of the present invention. FIG. 18 is an exploded view showing the structure of a wrinkle removing disk according to the fourth embodiment, and FIG. 18 is a view showing a wrinkle removing roller and a wrinkle removing disk attached state according to a fourth embodiment of the present invention.
[0069]
In the first embodiment, the larger the outer diameter of the wrinkle removing roller 16 is, the more effective the wrinkle removing roller 16 is against paper feed wrinkles. When a thick paper is fed, a jam is likely to occur.
[0070]
Therefore, in the present embodiment, as shown in FIGS. 15 and 16, the outer shape of the wrinkle removing roller 16 is reduced by holding the wrinkle removing roller 16 with a holder 23 urged downward by a spring 24. Since the same effect as in the case of increasing the size is obtained, and the wrinkle removing roller 16 is movable in the vertical direction, the load that the print medium receives from the paper transport route is not increased.
[0071]
Also, as shown in FIG. 1, the wrinkle removing disk 17 in the first embodiment cannot be moved up and down because it is formed integrally with the paper feed roller shaft 15. 17, the open holder 23 'having an oval hole through which the paper feed roller shaft 15 penetrates is urged downward by a spring 24' so that the holder 23 ' Can be solved by attaching.
[0072]
As shown in FIG. 17, the holder 23 of the wrinkle removing roller 16 is provided with an elongated hole-shaped engaging hole 23a for movably engaging the top guide 13 in the vertical direction in FIG. It is engaged with an engaging portion 25 attached to the top guide 13. The lower end of the holder 23 rotatably supports the wrinkle removing roller 16.
[0073]
As shown in FIG. 17, an elongated hole 23'a for engaging the top guide 13 in the holder 23 'of the wrinkle removing disk 17 so as to be vertically movable in FIG. And is engaged with an engaging portion 25 ′ attached to the top guide 13. The lower end of the holder 23 'rotatably supports the wrinkle removing disk 17. Further, at the lower end of the holder 23 ', an oval hole 23b' for penetrating the paper feed roller shaft 15 of the paper feed roller 14 is provided. The wrinkle removing disk 17 is provided with a circular hole so that the paper feed roller shaft 15 can pass therethrough.
[0074]
Then, as shown in FIG. 18, the wrinkle removing roller 16 and the wrinkle removing disk 17 are configured to rotate independently of the rotation of the paper feed roller 14. The wrinkle removing roller 16 and the wrinkle removing disk 17 are configured to rotate as the print medium is transported when the print media are separated one by one and transported by the paper feed roller 14. Therefore, the wrinkle removing roller 16 and the wrinkle removing disk 17 prevent wrinkles of the print medium and play a role of reducing the load at the time of transporting the print medium.
[0075]
As described above, in the present embodiment, the wrinkle removing roller 16 is structured to be held by the holder 23 urged downward by the spring 24, and the wrinkle removing disk 17 is held by the holder 23 urged downward by the spring 24 '. With the structure held by the ', the same effect as when the outer shape of the wrinkle removing roller 16 and the wrinkle removing disk 17 is increased, and the wrinkle removing roller 16 and the wrinkle removing disk 17 are movable in the vertical direction. Therefore, the paper route load does not increase.
[0076]
Also, by using the first to third embodiments in combination, it is possible to prevent the occurrence of wrinkles when feeding thin paper as a print medium, and it is possible to prevent thick paper from being fed as a print medium. Paper feed can be realized.
[0077]
It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.
[0078]
【The invention's effect】
As described above in detail, according to the present invention, in the paper feed mechanism, the fixed guide member disposed on the print medium transport route between the paper feed roller and the print medium transport roller, And a movable guide member which is urged in a direction to narrow a gap between the fixed guide and the fixed guide.
[0079]
In this case, since the gap between the fixed guide member and the movable guide member through which the print medium passes is reduced, it is possible to remove the wavy generated on the print medium and prevent wrinkles from occurring.
[Brief description of the drawings]
FIG. 1 is a first perspective view illustrating a configuration of a main part of a sheet feeding mechanism according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a printing apparatus having a conventional multi-purpose tray.
FIG. 3 is a second perspective view illustrating a configuration of a main part of the sheet feeding mechanism according to the first embodiment of the present invention.
FIG. 4 is a diagram illustrating a cassette sheet feeding route according to the first embodiment of the present invention.
FIG. 5 is an exploded view of a main part showing a configuration for mounting a wrinkle removal guide according to the first embodiment of the present invention.
FIG. 6 is a diagram showing a configuration of a wrinkle removing roller and a wrinkle removing disk according to the first embodiment of the present invention.
FIG. 7 is a sectional view of a main part of a sheet feeding mechanism according to the first embodiment of the present invention.
FIG. 8 is a table showing the urging force and the presence or absence of wrinkles in the first embodiment of the present invention.
FIG. 9 is a table showing the size of a gap and the occurrence of wrinkles in the first embodiment of the present invention.
FIG. 10 is a first perspective view of a wrinkle removing guide according to a second embodiment of the present invention.
FIG. 11 is a second perspective view of a wrinkle removing guide according to the second embodiment of the present invention.
FIG. 12 is a detailed view of a roller of a wrinkle removing guide according to a second embodiment of the present invention, and is an enlarged view of a portion D in FIG. 10;
FIG. 13 is a table showing the urging force and the occurrence of wrinkles in the second embodiment of the present invention.
FIG. 14 is a sectional view of a main part of a sheet feeding mechanism according to a third embodiment of the present invention.
FIG. 15 is a front view of a wrinkle removing roller according to a fourth embodiment of the present invention.
FIG. 16 is a perspective view of a wrinkle removing roller according to a fourth embodiment of the present invention.
FIG. 17 is an exploded view showing a structure of a wrinkle removing disk according to a fourth embodiment of the present invention.
FIG. 18 is a diagram illustrating a mounting state of a wrinkle removing roller and a wrinkle removing disk according to a fourth embodiment of the present invention.
[Explanation of symbols]
13 Top Guide
14, 21 Paper feed roller
16 Wrinkle removal roller
17 Disk for wrinkle removal
18 Wrinkle removal guide
19, 23a Registration roller
20, 23b Pressure roller
22 plunger
26 Coil spring

Claims (5)

(A) a fixed guide member disposed on a print medium transport route between a paper feed roller and a print medium transport roller;
(B) a paper feed mechanism, comprising: a movable guide member biased in a direction to narrow a gap between the print medium and the fixed guide. The paper feed mechanism according to claim 1, wherein the movable guide member includes a roller that is rotated by the print medium at a leading end. The paper feed mechanism according to claim 1, wherein the movable guide member includes a position regulating unit that automatically switches a gap between the movable guide member and the fixed guide according to a setting of the print medium. The paper feed mechanism according to claim 3, wherein the position restricting means is a plunger. The paper feed mechanism according to claim 1, further comprising a rotation guide member urged toward the print medium and swingably disposed on both sides of the paper feed roller.

Images