JP4337231B2 - Printing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printing apparatus, and more particularly, to a printing apparatus in which a paper feed roller and a paper discharge roller are provided before and after a printing area by an ink head.
[0002]
[Prior art]
6 and 7 illustrate the main parts of a conventional printing apparatus. In this printing apparatus, a paper feed roller 2 and a paper discharge roller 3 are distributed on the front side and the rear side across the paper support surface 12 of the platen 1, and the installation position of the paper feed roller 2 and the paper discharge roller 3 are arranged. A printing area Z by the ink head 4 is formed between the installation position of the ink head 4. The paper feed roller 2 feeds the paper 100 to the print area Z, while the paper discharge roller 3 discharges the paper 100 from the print area Z. Reference numeral 21 denotes a presser roller for pressing the paper 100 against the paper feed roller 2, 31 is a star wheel for preventing the paper 100 from floating from the paper discharge roller 3, and X is the moving direction of the ink head 4 in the print area Z, Y indicates the feeding direction of the paper 100. In FIG. 7, the paper feed roller 2 and the paper discharge roller 3 are represented by one roller having a long axial length, but each of these rollers 2 and 3 is a plurality of shafts having a short axial length provided coaxially. It may be formed by other rollers. Further, in FIG. 7, the rotation axis of the star wheel 31 is omitted, but these star wheels 31 have individual rotation axes. The pressing roller 21 is provided at a plurality of locations at predetermined intervals in the axial direction of a common rotating shaft (not shown).
[0003]
In this type of printing apparatus, the paper feed speed by the paper discharge roller 3 is set to be slightly higher than the paper feed speed by the paper feed roller 2. Therefore, the paper feed roller 2 gives a certain resistance to the paper fed by the paper discharge roller 3, and as a result, the paper 100 is pulled in the direction along the feed direction Y in the print region Z. Appropriate printing is performed.
[0004]
On the other hand, in Japanese Patent Laid-Open No. 11-245457, at the moment when the rear end of the paper fed by the paper discharge roller is separated from the paper feed roller, the vicinity of the rear end of the paper flutters and the print quality deteriorates. Disclosure of measures to solve this problem has been made.
[0005]
[Problems to be solved by the invention]
However, in the conventional printing apparatus described with reference to FIGS. 6 and 7, the paper feed speed by the paper discharge roller 3 is determined to be slightly higher than the paper feed speed by the paper feed roller 2. At the moment when the rear end 101 of the sheet 100 being fed by the sheet is pulled out from between the sheet feed roller 2 and the presser roller 21, the resistance applied to the sheet 100 by the sheet feed roller 2 disappears, and the sheet 100 A phenomenon occurs in which the moving speed is instantaneously faster than before, and this may cause the print quality in the vicinity of the rear end of the paper 100 to deteriorate.
[0006]
Therefore, in order to make the deterioration of the printing quality inconspicuous, a non-printing area U having a large width or a narrow width may be formed in the vicinity of the rear end 101 of the paper 100. Then, the printing range S of the paper 100 is narrowed.
[0007]
In this regard, according to the technique described in the above-mentioned Japanese Patent Application Laid-Open No. 11-245457, even if it is possible to suppress flapping of the paper at the moment when the trailing edge of the paper is separated from the paper feed roller, at that moment It is impossible to suppress a decrease in print quality due to an increase in paper feed speed.
[0008]
The present invention has been made under the above circumstances, and not only can the fluttering of the paper at the moment when the trailing edge of the paper is separated from the paper feeding roller be suppressed, but also the trailing edge of the paper is separated from the paper feeding roller. It is an object of the present invention to provide a printing apparatus capable of suppressing a decrease in print quality due to waving in the width direction of a sheet afterwards without narrowing the print range of the sheet.
[0009]
It is another object of the present invention to provide a printing apparatus that can suppress a decrease in print quality due to an increase in paper feed speed at the moment when the trailing edge of the paper is separated from the paper feed roller.
[0010]
[Means for Solving the Problems]
The printing apparatus according to the present invention is configured such that the paper feed roller is disposed between an installation position of a paper feed roller for feeding the paper into a print area by the ink head and an installation position of a paper discharge roller for discharging the paper from the print area. Paper holding means is provided for holding the outer position in the width direction of the print range of the paper discharged from the paper discharge roller away from the roller.
[0011]
In this printing apparatus, the flapping of the paper at the moment when the trailing edge of the paper is separated from the paper feed roller is suppressed by the paper holding means that holds the outer position in the width direction of the printing range of the paper. In addition, the paper holding means holds the outer position in the width direction of the print range of the paper even when the print quality deteriorates due to the waviness in the width direction of the paper after the trailing edge of the paper is separated from the paper feed roller. It is suppressed by. In the present invention, it is desirable that the paper holding means be provided as close to the paper feeding device as possible within a range that does not interfere with the operation of the ink head. By doing so, the print quality near the rear edge of the paper is improved. This will improve the printing range.
[0012]
In the present invention, the sheet holding means includes a support member that supports the back surface of the sheet from below, and a pressing roller that presses the width direction outer side position of the print range of the sheet from above on the support member. As the support member, it is possible to employ a rotating roller or a platen on which the paper fed into the print area comes into sliding contact.
[0013]
In the present invention, in the case where a rotating roller is used as the supporting means, the timing gears fixed to the rotating shaft of the paper feeding roller and the rotating shaft of the paper discharging roller to which the rotation of the driving motor is transmitted are connected by the timing belt. In addition, a timing gear fixed to the rotation shaft of the paper feed roller and a timing gear fixed to the rotation shaft of the rotation roller are connected by a timing belt, and the paper discharge speed is higher than the paper feed speed of the paper feed roller. The paper feed roller is set to increase the paper feed speed by the roller and the paper feed roller gives resistance to the paper fed by the paper discharge roller, and is equal to or substantially equivalent to the resistance given by the paper feed roller to the paper. Is applied to the paper by the rotating roller, and after the trailing edge of the paper is separated from the paper feeding roller, Feed speed of the sheet has a function to prevent the faster momentarily by the paper holding means. In the present invention, in the case where a platen is used as the supporting means, the sheet feeding speed is determined so that the sheet feeding speed by the sheet discharging roller is higher than the sheet feeding speed by the sheet feeding roller, and the sheet is fed to the sheet fed by the sheet discharging roller. The roller applies resistance, and the rear end of the paper feeds the paper by applying the same resistance as or substantially equivalent to the resistance applied by the paper feed roller to the paper. The drive roller has a function of preventing the paper feed speed from being instantaneously increased by the paper holding means after being separated from the roller.
[0014]
According to this, after the trailing edge of the paper sent by the paper discharge roller is separated from the paper supply roller, resistance is applied to the paper by the paper holding means, and the resistance applied to the paper by the paper holding means is Since the paper feed roller is equivalent to or nearly equivalent to the resistance applied to the paper, the paper feed speed does not increase instantaneously, resulting in a decrease in print quality due to a sudden change in the paper feed speed. Also does not happen.
[0015]
Furthermore, in the printing apparatus according to the present invention, it is possible to employ a configuration in which the paper holding unit applies a diagonally outward feeding force to the outer position in the width direction of the print range of the paper. is there. According to this, the sheet holding means acts to pull in the width direction with respect to the rear end of the sheet away from the sheet feeding roller. As a result, no waviness in the width direction occurs at the rear end of the sheet away from the sheet feeding roller, and the print quality is further improved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a side view illustrating the main part of the printing apparatus according to the first embodiment of the present invention, and FIG. 2 is a plan view illustrating the main part.
[0017]
The printing apparatus shown in FIGS. 1 and 2 is different from the conventional printing apparatus described with reference to FIGS. 6 and 7 in that the sheet holding means 5 is provided between the installation position of the paper feed roller 2 and the installation position of the paper discharge roller 3. This is the point. Since other matters are the same as those described with reference to FIGS. 6 and 7, the same reference numerals are given to the same portions in order to avoid duplication of description.
[0018]
The paper holding means 5 holds the left and right width direction outer positions S1 and S1 of the printing range S of the paper 100 that is separated from the paper supply roller 2 and discharged by the paper discharge roller 3. In this embodiment, the sheet holding means 5 includes a rotating roller 51 as a support member that supports the back surface of the sheet 100 from below, and left and right widthwise outer positions S1 and S1 of the printing range S of the sheet 100 on the rotating roller 51. It is comprised by the press rollers 52 and 52 pressed from the top. The rotating roller 51 and the pressing rollers 52 and 52 can be attached to a bearing (not shown) formed integrally with the platen 1. The rotating roller 51 can be provided separately for the left and right pressing rollers 52, 52.
[0019]
As in this embodiment, the paper 100 is held in a negative pressure state by the rotating roller 51 and the pressing roller 52 between the installation position of the paper feed roller 2 and the installation position of the paper discharge roller 3. Then, flapping of the paper 100 at the moment when the rear end 101 of the paper 100 is separated from the paper feed roller 2 is suppressed by the repulsive action of the rotating roller 51 and the pressing roller 52. Further, since the waviness or the like in the width direction of the paper 100 after the rear end 101 of the paper 100 is separated from the paper feed roller 2 does not occur, the deterioration of the print quality due to the wave of the paper 100 is similarly suppressed. It is done.
[0020]
FIG. 3 is a side view illustratively showing a main part of the printing apparatus according to the second embodiment of the present invention. This printing apparatus is different from the printing apparatus described with reference to FIGS. 1 and 2 only in that a support member that supports the back surface of the paper 100 from below is formed by the platen 1. According to this, the fluttering of the paper 100 at the moment when the rear end 101 of the paper 100 is separated from the paper feed roller 2 is suppressed by the repressing action of the paper support surface 12 of the platen 1 and the pressing roller 52. Further, since the waviness or the like in the width direction of the paper 100 after the rear end 101 of the paper 100 is separated from the paper feed roller 2 does not occur, the deterioration of the print quality due to the wave of the paper 100 is similarly suppressed. It is done. In FIG. 3, in order to avoid duplication of description, the same parts as those described in FIGS. 1 and 2 are denoted by the same reference numerals.
[0021]
FIG. 4 is a plan view illustratively showing a main part of a printing apparatus according to the third embodiment of the present invention. In this printing apparatus, the difference from the first embodiment and the second embodiment described above is that the sheet holding means 5 has arrows a, a with respect to the left and right width direction outer positions S1, S1 of the printing range S of the sheet 100. As shown in Fig. 4, the feed force is applied obliquely outward. Also in this embodiment, the sheet holding means 5 supports a support member (not shown) that supports the back surface of the sheet 100 from below, and the left and right widthwise outer positions S1 and S1 of the print range S of the sheet 100 are placed on the support member. And a pressing roller 52 that is pressed from the outside. Then, by tilting the rotation axis 53 of the pressing roller 52 in the sheet feeding direction, an obliquely outward feeding force can be applied to the sheet 100. As the support member of the sheet holding means 5, the rotating roller 51 as described with reference to FIGS. 1 and 2 can be used, or the platen 1 as described with reference to FIG. 3 can be used.
[0022]
According to this embodiment, the sheet holding means 5 acts so as to pull in the width direction with respect to the rear end 101 of the sheet 100 away from the sheet feeding roller. For this reason, a wave in the width direction does not occur at the rear end 101 of the paper 100 away from the paper supply roller, and the print quality is further improved.
[0023]
Incidentally, as described for the conventional printing apparatus of FIGS. 6 and 7, in the printing apparatus, the paper feed speed by the paper discharge roller 3 is determined to be higher than the paper feed speed by the paper feed roller 2. The paper feed roller 2 gives resistance to the paper 100 fed by the paper roller 3. Therefore, it is desirable that the paper holding means 5 described above also has a function of giving the paper 100 a resistance equivalent or substantially equivalent to the resistance given to the paper 100 by the paper feed roller 2. If the trailing edge 101 of the paper 100 fed by the paper discharge roller 3 is separated from the paper feed roller 2, resistance is applied to the paper 100 by the paper holding means 5 and the paper 100 feed speed is instantaneously changed. The situation of becoming faster will not occur. For this reason, the print quality is not lowered due to a sudden change in the paper feed speed.
[0024]
FIG. 5 exemplifies a specific structure for imparting resistance to the paper 100 when the rotating roller 51 shown in FIG. 1 is employed as a supporting member of the paper holding means. In the figure, reference numeral 25 denotes a rotation shaft of the paper feed roller 2 and reference numeral 35 denotes a rotation shaft of the paper discharge roller 3. Timing gears 26 and 36 are fixed to the rotation shafts 25 and 35, respectively. At the same time, the timing gears 26 and 36 are connected by a timing belt 61. Reference numeral 55 denotes a rotating shaft of the rotating roller 51, and a timing gear 56 fixed to the rotating shaft 51 and another timing gear 27 fixed to the rotating shaft 25 of the paper feeding roller 2 are connected by a timing belt 62. ing. The rotation of a drive motor (not shown) is transmitted to the rotation shaft 25 of the paper feed roller 2. Therefore, when the rotary shaft 25 rotates and the paper feed roller 2 rotates, the rotary shaft 35 of the paper discharge roller 3 and the rotary shaft 55 of the rotary roller also rotate in synchronization therewith. In this case, if the number of teeth of each timing gear 26, 27, 36, 56 is appropriately selected, the diameters of the paper feed roller 2, the paper discharge roller 3, the rotation roller 51, etc. are appropriately selected. A resistance equivalent to or substantially equivalent to the resistance applied to the paper 100 by the paper feed roller 2 is applied to the paper by the paper holding means including the rotation roller 51.
[0025]
In FIG. 5, the rotating roller 51 shown in FIG. 1 is shown as a supporting member of the paper holding means. However, this point is that the pressing roller 52 described in FIGS. It is also possible to impart resistance to the.
[0026]
【The invention's effect】
As described above, according to the present invention, not only the flapping of the paper at the moment when the trailing edge of the paper fed by the paper discharge roller is separated from the paper feeding roller, but also the trailing edge of the paper is separated from the paper feeding roller. It is possible to suppress a decrease in print quality due to waving in the width direction of the paper after printing. In addition, since it is possible to improve the print quality by suppressing the deterioration of the print quality due to the increase in the paper feed speed at the moment when the trailing edge of the paper is separated from the paper feed roller, printing in the paper feed direction is possible. The range can be expanded as compared with the conventional case. In particular, it is possible to improve the print quality when printing graphics and photographs.
[Brief description of the drawings]
FIG. 1 is a side view illustratively showing a main part of a printing apparatus according to a first embodiment of the present invention.
FIG. 2 is a plan view illustratively showing the main part.
FIG. 3 is a side view illustratively showing a main part of a printing apparatus according to a second embodiment of the present invention.
FIG. 4 is a plan view illustratively showing a main part of a printing apparatus according to a third embodiment of the present invention.
FIG. 5 is an explanatory diagram illustrating a specific structure for imparting resistance to a sheet.
FIG. 6 is a side view illustratively showing a main part of a conventional printing apparatus.
FIG. 7 is a plan view illustratively showing main parts of a conventional printing apparatus.
[Explanation of symbols]
1 Platen (support member)
2 Paper feed roller 3 Paper discharge roller 4 Ink head 5 Paper holding means 51 Rotating roller (support member)
52 Pressing roller 100 Paper Z Printing area S Paper printing range S1 Outside width direction position of printing range

Claims (3)

The paper discharge roller is spaced apart from the paper feed roller between the installation position of the paper feed roller for feeding the paper to the print area by the ink head and the paper discharge roller for discharging the paper from the print area. In a printing apparatus comprising paper holding means for holding the position in the width direction outside the print range of the paper discharged by
The paper holding means has a support member that is formed by a rotating roller and supports the back side of the paper from below, and a pressing roller that presses the width direction outer side position of the print range of the paper from above on the support member,
Timing gears fixed to the rotation shaft of the paper feed roller to which the rotation of the drive motor is transmitted and the rotation shaft of the paper discharge roller are connected by a timing belt and fixed to the rotation shaft of the paper feed roller. The gear and a timing gear fixed to the rotating shaft of the rotating roller are connected by a timing belt, and the sheet discharging speed is determined so that the sheet feeding speed by the sheet discharging roller is faster than the sheet feeding speed by the sheet feeding roller. The paper feed roller gives resistance to the paper fed by the above, and the rotary roller gives resistance equal to or substantially equivalent to the resistance given to the paper by the paper feed roller. After the trailing edge of the paper is separated from the paper feed roller, the paper holding speed can be increased instantaneously by the paper holding means. Printing apparatus characterized in that it has a tool function. The paper discharge roller is spaced apart from the paper feed roller between the installation position of the paper feed roller for feeding the paper to the print area by the ink head and the paper discharge roller for discharging the paper from the print area. In a printing apparatus comprising paper holding means for holding the position in the width direction outside the print range of the paper discharged by
The paper holding means is formed by a platen that is slidably contacted with the paper fed into the printing area and supports the back surface of the paper from below, and presses the width direction outer side position of the paper printing range from above onto the support member. A pressing roller,
The sheet feed roller is provided with a resistance to the sheet fed by the sheet discharge roller so that the sheet feed speed by the sheet discharge roller is faster than the sheet feed speed by the sheet feed roller, and the pressure roller Is applied to the paper by a resistance equivalent to or substantially equal to the resistance applied to the paper by the paper supply roller, and then the paper feed speed is adjusted by the paper holding means after the rear edge of the paper is separated from the paper supply roller. The printing apparatus is characterized by being a drive roller having a function of preventing the ink from being instantaneously increased .   The printing apparatus according to claim 1, wherein the paper holding unit applies an obliquely outward feeding force to an outer position in the width direction of the print range of the paper.

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