JP2001310516A - Printing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a printing range of a paper with suppressing a lowering of print quality due to a sudden change of feeding speed of the paper and also to improve a print quality of the paper with suppressing fluttering and skewing of the paper in a printing apparatus. SOLUTION: A paper holding means 5 which supports lateral parts of the printing range of a paper 100 in the breadthwise direction between a setting position of a paper feeding roller 2 and a setting position of a paper discharging roller 3 is provided. The paper holding means 5 includes a rotating roller 51 as a support member which supports the back of the paper 100 upwards and a pressing roller 52 which presses the lateral parts of the printing range of the paper 100 downwards.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing device,
The present invention relates to a printing apparatus in which a paper feed roller and a paper discharge roller are provided before and after a print area by an ink head.

[0002]

2. Description of the Related Art FIGS. 6 and 7 illustrate principal parts of a conventional printing apparatus. In this printing apparatus, a paper feed roller 2 and a paper discharge roller 3 are separately arranged on a front side and a rear side of a paper support surface 12 of a platen 1, and an installation position of the paper feed roller 2 and a paper discharge roller 3 are arranged. A printing area Z formed by the ink head 4 is formed between the position and the installation position. And
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 pressing roller for pressing the paper 100 against the paper feed roller 2, and 31 denotes a paper 1
Reference numeral 00 denotes a star wheel for preventing the ink head 4 from rising from the paper discharge roller 3,
Y indicates the feeding direction of the sheet 100. FIG.
, 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 provided with a plurality of coaxially provided rollers having a short axial length. It may be formed by. Although the rotation axis of the star wheel 31 is not shown in FIG. 7, these star wheels 31 have individual rotation axes. The pressing rollers 21 are provided at a plurality of locations at predetermined axial intervals of a common rotating shaft (not shown).

In this type of printing apparatus, the paper feed speed of the discharge roller 3 is set to be slightly higher than the paper feed speed of the paper feed roller 2. for that reason,
The paper feed roller 2 applies a certain resistance to the paper fed by the paper discharge roller 3, and as a result, the paper 100 is pulled in the feed direction Y in the print area Z. And proper printing is performed.

On the other hand, Japanese Patent Application Laid-Open No. H11-245457 discloses that, at the moment when the trailing end of a sheet being fed by a sheet discharging roller is separated from the sheet feeding roller, the vicinity of the trailing end of the sheet flutters and print quality is reduced. There are disclosures about countermeasures to solve the problem of a decrease in the number of people.

[0005]

However, FIG. 6 and FIG.
In the conventional printing apparatus described above, the paper feed speed of the paper discharge roller 3 is set to be slightly higher than the paper feed speed of the paper feed roller 2, so that the paper 100 fed by the paper discharge roller 3 At the moment when the trailing end 101 comes out of the space between the paper feed roller 2 and the press roller 21, the resistance applied to the paper 100 by the paper feed roller 2 disappears, and the moving speed of the paper 100 becomes higher than before. A phenomenon that the printing speed is instantaneously increased occurs, and as a result, the printing quality near the rear end of the paper 100 may be reduced.

Therefore, in order to make such a decrease in print quality inconspicuous, a non-print area U having a slightly wide width may be formed near the rear end 101 of the paper 100. In such a case, the printing range S of the paper 100 becomes narrow.

In this regard, Japanese Patent Application Laid-Open No. H11-245 mentioned above is disclosed.
According to the technology described in Japanese Patent No. 457, even if the fluttering of the paper at the moment when the trailing edge of the paper separates from the paper feed roller can be suppressed, the print quality can be improved by increasing the paper feeding speed at that moment. Can not be suppressed.

The present invention has been made under the above circumstances, and can not only suppress the fluttering of the sheet at the moment when the trailing edge of the sheet is separated from the sheet feeding roller, but also reduce the sheet feeding at the trailing edge of the sheet. It is an object of the present invention to provide a printing apparatus capable of suppressing a decrease in print quality due to, for example, waving in the width direction of a sheet after leaving a roller without reducing the print range of the sheet.

Another object of the present invention is to provide a printing apparatus capable of suppressing a decrease in print quality due to an increase in the paper feeding speed at the moment when the trailing edge of the paper is separated from the paper feed roller. .

[0010]

According to the present invention, there is provided a printing apparatus in which a paper feed roller for feeding paper to a print area by an ink head and a paper discharge roller for discharging paper from the print area are provided. A paper holding unit that holds a position outside the printing range in the width direction of the paper discharged from the paper feed roller and discharged by the paper discharge roller between the paper feed rollers.

In this printing apparatus, the fluttering of the paper at the moment when the rear end of the paper is separated from the paper feeding roller is suppressed by the paper holding means which holds the position outside the printing range of the paper in the width direction. In addition, when the print quality deteriorates due to waving in the width direction of the paper after the trailing edge of the paper is separated from the paper feed roller, the paper holding means may hold the position outside the print range of the paper in the width direction. Is suppressed by. In the present invention, it is preferable that the paper holding means is provided at a position as close to the paper feeding device as possible as long as the operation of the ink head is not hindered, and by doing so, the print quality near the rear end of the paper is improved. It is easier to expand the printing range by improving the printing range.

The paper holding means may have a support member for supporting the back surface of the paper from below, and a pressing roller for pressing the support member from above on a position outside the printing range of the paper in the width direction. In this case, it is possible to employ a rotating roller as the support member, or a platen with which the paper fed into the print area slides. When a rotating roller is used as the support member, the sheet is fed without slipping between the rotating roller and the pressing roller while the sheet is sandwiched between the rotating roller and the pressing roller. Further, when a platen is used as the support member, the paper is fed by sliding on the platen.

Further, in the printing apparatus according to the present invention, the paper feed speed of the paper discharge roller is determined to be higher than the paper feed speed of the paper feed roller, and the paper feed roller feeds the paper fed by the paper discharge roller. It is preferable that the sheet holding means has a function of applying a resistance to the sheet equal to or substantially equal to the resistance applied to the sheet by the paper feed roller.

According to this, after the trailing end of the sheet sent by the sheet ejection roller is separated from the sheet feeding roller, the sheet holding means applies resistance to the sheet, and the sheet holding means applies resistance to the sheet. Is equivalent to or approximately equal to the resistance that the paper feed roller has applied to the paper up to that point, so that the situation where the paper feed speed increases instantaneously does not occur, and as a result, printing accompanying a sudden change in the paper feed speed Degradation does not occur.

Further, in the printing apparatus according to the present invention, a configuration is adopted in which the paper holding means applies an obliquely outward feeding force to an outer position in the width direction of the printing range of the paper. Is possible. According to this, the sheet holding means acts to pull in the width direction with respect to the rear end of the sheet separated from the sheet feeding roller. For this reason, the widthwise undulation or the like does not occur at the trailing end of the sheet away from the sheet feeding roller, and the print quality is further improved.

[0016]

FIG. 1 is a side view for explaining a main part of a printing apparatus according to a first embodiment of the present invention, and FIG. 2 is a plan view for explaining the main part. .

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 a paper sheet is provided between a position at which a paper feed roller 2 and a paper discharge roller 3 are provided. The point is that the holding means 5 is provided. Other items are the same as those described with reference to FIGS. 6 and 7, and the same reference numerals are given to the same portions in order to avoid redundant description.

The sheet holding means 5 holds the left and right widthwise outside positions S1 and S1 of the printing range S of the sheet 100 discharged by the sheet discharging roller 3 away from the sheet feeding roller 2. In this embodiment, the sheet holding means 5
A rotating roller 51 as a support member for supporting the back surface of the sheet 100 from below, and pressing rollers 52, 52 for pressing the rotating rollers 51 from above on left and right lateral positions S1, S1 of the printing range S of the sheet 100 from above. It is constituted by. The rotating roller 51 and the pressing rollers 52, 52
Can be attached to a bearing (not shown) formed integrally with the platen 1. Also, the rotating roller 51
Can be provided separately for the left and right pressing rollers 52, 52.

As in this embodiment, the paper 100 is set between the position where the paper feed roller 2 is set and the position where the discharge roller 3 is set.
Is held in a state of being pressed by the rotating roller 51 and the pressing roller 52, the fluttering of the sheet 100 at the moment when the rear end 101 of the sheet 100 is separated from the sheet feeding roller 2, The pressure is suppressed by the pressing action by the pressing roller 52. Also, the rear end 101 of the paper 100
Does not occur in the width direction of the paper 100 after the paper 100 has been separated from the paper feed roller 2.
The deterioration of the print quality due to the waving is also suppressed.

FIG. 3 is a side view illustratively showing a main part of a printing apparatus according to a second embodiment of the present invention. This printing apparatus differs 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 sheet 100 from below is formed by a platen 1. According to this, the fluttering of the sheet 100 at the moment when the rear end 101 of the sheet 100 separates from the sheet feeding roller 2 is suppressed by the pressing action between the sheet supporting surface 12 of the platen 1 and the pressing roller 52. In addition, since the paper 100 does not undulate in the width direction after the trailing edge 101 of the paper 100 is separated from the paper feed roller 2, the deterioration of print quality due to the undulation of the paper 100 is similarly suppressed. . In FIG. 3, the same parts as those described in FIGS. 1 and 2 are denoted by the same reference numerals in order to avoid redundant description.

FIG. 4 is a plan view for explaining principal parts of a printing apparatus according to a third embodiment of the present invention. This printing apparatus is different from the above-described first and second embodiments in that the sheet holding means 5 moves the arrows a,
As shown by a, it has a function of giving a diagonally outward feed force. Also in this embodiment, the paper holding means 5 has a support member (not shown) for supporting the back surface of the paper 100 from below, and a print area S of the paper 100 on the support member.
And a pressing roller 52 for pressing the left and right widthwise outside positions S1 and S1 from above. By inclining the rotation axis 53 of the pressing roller 52 in the paper feeding direction, a feeding force obliquely outward can be applied to the paper 100. Note that, as the support member of the sheet holding means 5, the rotating roller 51 described with reference to FIGS. 1 and 2 can be used, or the platen 1 described with reference to FIG. 3 can be used. When the rotation roller 51 is used as the supporting member, the rotation axis (not shown) of the rotation roller 51 may be inclined at the same angle as the rotation axis of the pressing roller 52 in the same direction with respect to the sheet feeding direction. Desirably, the paper 100 can be smoothly fed in the feed direction while being pulled in the width direction by being sandwiched between the left and right rotating rollers 51 and the pressing roller 52. Does not occur, and the print quality near the trailing edge 101 of the paper 100 is greatly improved.

According to this embodiment, the paper holding means 5 acts to pull the rear end 101 of the paper 100 away from the paper feed roller in the width direction. As a result, the trailing edge 101 of the sheet 100 distant from the sheet feeding roller does not wrinkle in the width direction, and the print quality is further improved.

As described with reference to the conventional printing apparatus shown in FIGS. 6 and 7, in the printing apparatus, the paper feed speed of the discharge roller 3 is set to be faster than the paper feed speed of the paper feed roller 2. And the paper discharge roller 3
The paper feed roller 2 applies resistance to the paper 100 fed by the printer. Therefore, it is desirable that the above-described paper holding means 5 also has a function of applying to the paper 100 a resistance equal to or substantially equal to the above-described resistance that the paper feed roller 2 applies to the paper 100. After the trailing end 101 of the paper 100 sent by the paper discharge roller 3 is separated from the paper feed roller 2, the paper holding means 5 applies resistance to the paper 100 and the paper 100
A situation in which the feed speed of the feed increases instantaneously does not occur. Therefore, the print quality does not deteriorate due to the sudden change in the paper feed speed.

FIG. 5 shows a case where the rotating roller 51 shown in FIG.
A specific structure for giving resistance to 00 is illustrated. In the figure, reference numeral 25 denotes a rotation axis of the paper feed roller 2;
Are the rotating shafts of the discharge rollers 3 and their respective rotating shafts 2
Timing gears 26 and 36 are fixed to each of the gears 5 and 35, and the timing gears 26 and 36
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 the feeding roller 2.
The other timing gear 27 fixed to the rotating shaft 25 is connected by a timing belt 62. The rotation of a drive motor (not shown) is transmitted to the rotation shaft 25 of the paper feed roller 2. Therefore, when the rotation shaft 25 rotates and the paper feed roller 2 rotates, the rotation shaft 35 of the discharge roller 3 and the rotation shaft 5 of the rotation roller are synchronized with the rotation.
5 also rotates. In this case, the timing gears 26, 2
If the number of teeth of 7, 36, 56 is properly selected, and the diameters of the paper feed roller 2, the paper discharge roller 3, and the rotating roller 51 are appropriately selected, the paper feed roller 2 The resistance equal or substantially equal to the resistance to be applied
Is applied to the sheet by the sheet holding means provided with.

FIG. 5 shows the rotary roller 51 shown in FIG. 1 as a support member of the sheet holding means, but this point is the same as that of the pressing roller 52 described with reference to FIGS. It is also possible to apply resistance to the sheet by means of 52.

[0026]

As described above, according to the present invention, not only the flutter of the paper at the moment when the trailing edge of the paper fed by the paper discharge roller is separated from the paper feed roller is suppressed, but also the trailing edge of the paper is A decrease in print quality due to waving in the width direction of the paper after leaving the paper feed roller can be suppressed. Also,
Immediately after the trailing edge of the paper separates from the paper feed roller, it is possible to improve the print quality by suppressing the decrease in print quality due to the increase in the paper feed speed. It becomes possible to enlarge it more than the conventional case. In particular, it is possible to improve print quality when printing graphics, photographs, and the like.

[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 view exemplifying 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 a main part of a conventional printing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Platen (support member) 2 Paper feed roller 3 Discharge roller 4 Ink head 5 Paper holding means 51 Rotating roller (support member) 52 Press roller 100 Paper Z Print area S Print area of paper S1 Outside position in the width direction of print area

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65H 29/70 B41J 3/04 101Z

Claims (6)

[Claims] 1. An image forming apparatus according to claim 1, wherein a position of a paper feed roller for feeding the paper to a print area by an ink head and a position of a paper discharge roller for discharging the paper from the print area are provided.
A printing apparatus, comprising: paper holding means for holding a position outside a printing range of a paper discharged from the paper feed roller by the paper discharge roller in a width direction. 2. The paper holding device according to claim 1, wherein the paper holding means has a support member for supporting the back surface of the paper from below, and a pressing roller for pressing the support member from above the outer position in the width direction of the printing range of the paper. Printing device. 3. The printing apparatus according to claim 2, wherein said support member is a rotating roller. 4. The printing apparatus according to claim 2, wherein the support member is a platen with which a sheet fed into the print area comes into sliding contact. 5. The paper feed speed of the discharge roller is determined to be faster than the paper feed speed of the paper feed roller, and the paper feed roller applies resistance to the paper fed by the paper discharge roller. The printing according to any one of claims 1 to 4, wherein the paper holding means has a function of applying to the paper a resistance equal to or substantially equal to the resistance applied to the paper by the paper feed roller. apparatus. 6. The printing apparatus according to claim 2, wherein the paper holding means applies a feeding force obliquely outward to a position outside the printing range of the paper in the width direction.