JP2003002547A - Double-sided printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double-sided printer capable of carrying out double-sided printing while minimizing the configuration size and the number of parts and easily applicable to an ordinary ink-jet printer. SOLUTION: This double-sided printer is provided with first conveying passages 5 and 6 conveying paper 1 in the paper delivery direction, a freely rotational guide 11 facing a paper delivery roller 10, a second conveying passage 7 conveying the paper reversed by the guide 11 in the direction opposite to the paper delivery direction, a feed roller 9 in common between the first and second conveying passages, a feed-in roller 8 guiding the paper conveyed through the second conveying passage to a paper accumulating part A, and guides 13 and 14. In double-sided printing, the paper printed on one side is turned around in the opposite direction by means of the raised guide 1 to be led to the paper accumulating part A from the second conveying passage 7, and then, the paper is fed out to the first conveying passages 5 and 6 to be printed on the other side. Subsequently, the guide 11 is folded down and the paper printed on both sides is delivered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided printing printer capable of printing on the front and back of paper.

[0002]

2. Description of the Related Art Various types of duplex printers have been proposed so far. For example, Japanese Patent Laid-Open No. 6-1
Japanese Laid-Open Patent Publication No. 10274 describes a sheet reversing unit attached to the main body of the printer to enable double-sided printing. Further, Japanese Patent Laid-Open No. 62-186277 discloses a double-sided printing printer in which a sheet for which one-sided printing has been completed is temporarily returned to a paper feeding cassette and then fed again from the paper feeding cassette to perform printing on the back surface. Has been done.

[0003]

However, the former one has a drawback that it has a large size and requires a large installation space because it has a structure in which the reversing unit is mounted outside the printer body. Further, in the latter, the paper is reversed inside the printer body, so the drawback of the former can be solved, but a roller for conveying the reversed paper is separately required, and the number of parts increases and the structure is complicated. There is a problem that becomes. Further, since the printers described in these publications are all laser printers, it is difficult to apply them as they are to inkjet printers having basically different structures.

On the other hand, Japanese Utility Model Laid-Open No. 64-55047 and Japanese Utility Model Laid-Open No. 4-45750 also describe a double-sided printing printer which reverses the paper on which the printing on the front side is finished and prints on the back side. However, since the printers described in these publications have a special structure, it is still difficult to apply them to general inkjet printers.

The present invention is intended to solve the above-mentioned problems, and the problem is that double-sided printing is possible while minimizing the external dimensions and the number of parts, and general inkjet It is to provide a double-sided printing printer that can be easily applied to a printer.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, only the front surface is printed at the discharge side end of a first conveying path for conveying a sheet fed by a sheet feeding roller. A reversing unit for reversing the formed sheet and switching the conveying direction to a direction opposite to the sheet discharging direction is provided, and a second conveying path for conveying the sheet whose sheet is reversed by the reversing unit and the conveying direction is changed. Then, a common feed roller is provided in each of these transport paths to transport the paper in the first transport path in the paper discharge direction, and transport the paper in the second transport path in the direction opposite to the paper discharge direction. Further, there is provided a guide unit that sends the sheet conveyed through the second conveying path upward and guides the sheet to the sheet accumulating unit. At the time of double-sided printing, the sheet whose surface is printed in the first transport path is guided to the second transport path by the reversing means, and is guided from the second transport path to the paper stacking section through the guiding means, and then the paper is transferred to the first transport path. Then, the sheet is sent to the conveyance path No. 1, the back side is printed, and the sheet with both sides printed is discharged.

By doing so, it is possible to perform double-sided printing on paper without mounting a separate unit, and it is possible to suppress an increase in the external size of the printer. Further, since the feed roller in the case where the sheet is turned upside down and conveyed in the second conveying path is also used as the feed roller in the first conveying path, a separate roller is used for conveying the sheet in the reverse direction. Is not required, and the structure of the transport mechanism is simplified. Further, the present invention can realize the double-sided printing function by adding a slight configuration to the existing inkjet printer.

[0008]

1 is a schematic configuration diagram of an inkjet printer according to an embodiment of the present invention. In the figure, 1 is a sheet accumulated in a sheet accumulating section A, 2 is a mounting table for the sheet 1, 3 is a lever supporting a sheet feeding roller 4, and 4 is a sheet for accumulating the sheet 1 in the sheet accumulating section A one by one. Paper feed rollers 5 and 6 are upper plates to which the paper fed by the paper feed rollers 4 is conveyed in the paper discharge direction (left in the figure), and 7 is a lower plate provided below the upper plates 5 and 6. Is. The upper plates 5 and 6 form the first conveyance path of the present invention, and the lower plate 7 forms the second conveyance path of the present invention.

Reference numeral 8 is a delivery roller located between the mounting table 2 and the upper plate 5, 9 is a feed roller located between the upper plates 5 and 6, and 10 is a paper ejection roller for ejecting printed paper. Reference numeral 11 denotes a guide (first guide) provided so as to be displaceable in opposition to the paper discharge roller, 12 is a rotating shaft of the guide 11, and 13 is provided at an end portion of the lower plate 7 so as to oppose the delivery roller 8. Guide (second guide),
14 is a guide (third part) provided above the feeding roller 8.
Of the guide), 15 is a slit formed between the feed roller 8 and the guide 13, and 16 is a printing unit for printing on the paper conveyed on the upper plates 5 and 6. The paper discharge roller 10 and the guide 11 constitute the reversing means of the present invention, and the delivery roller 8, the guide 13 and the guide 14 constitute the guiding means of the present invention.

FIG. 2 is a block diagram showing the electrical construction of the printer. Only the blocks relevant to the present invention are shown here. 20 is a CP constituting a control unit
U and 21 are ASICs (Application Specific ICs) that execute various operations based on commands from the CPU 20;
2 is a motor driver for driving the motor, 23 is a feed motor for conveying the paper, and 24 is a guide 11
A motor for rotating the motor, 25 is a memory including a RAM, and 16 is the printing unit described above. The paper feed roller 4, the feed roller 9, the paper discharge roller 10, and the delivery roller 8 are interlocked via a belt (not shown) and are driven to rotate by a common feed motor 23. The guide 11 is rotated by the motor 24 about the rotation shaft 12 and can be displaced between the solid line position and the broken line position shown in FIG.

FIG. 3 to FIG. 12 are operation explanatory views when performing double-sided printing with the printer described above. The operation of double-sided printing will be described below according to this. When the printer is set to the double-sided printing mode and the feed motor 23 is driven,
The sheet feeding roller 4 rotates to feed out the sheets 1 stacked in the sheet stacking unit A one by one. As shown in FIG. 3, the fed-out sheet 1a has upper plates 5 and 6 that form a first transport path.
Is transported by the feed roller 9 and, in the process,
The printing unit 16 prints on one surface (front surface) of the paper 1a.

The sheet 1a for which single-sided printing has been completed is conveyed in the sheet discharge direction and reaches the sheet discharge roller 10. At this time, since the guide 11 is in an upright state, the sheet 1a is guided by the guide 11 as shown in FIG. Make a U-turn along. That is, the front and back sides of the sheet 1a are reversed by the guide 11, and the conveyance direction is switched to the direction opposite to the sheet discharge direction (right direction in the figure), and as shown in FIG. 5, the lower plate forming the second conveyance path. It is conveyed by a feed roller 9 on top of 7. That is, the feed roller 9 is commonly provided in the first and second conveying paths. Although the distance between the feed roller 9 and the lower plate 7 is exaggerated in the drawing for the sake of convenience, in practice, this distance is set to a minute distance that allows the paper 1a to pass through. .

The leading edge (right edge) of the sheet 1a is the lower plate 7.
When it reaches the delivery roller 8 provided at the end portion of the sheet 1, the sheet 1a is guided by the guide 13 and turned upward as shown in FIG.
It is sent out from 5. After that, when the delivery roller 8 continues to rotate further, as shown in FIG. 7, the sheet 1a delivered from the slit 15 is switched to the sheet feeding roller 4 by the guide 14 and fed to the sheet stacking unit A. I'm going down. At this time, since the paper feed roller 4 is rotating in the direction opposite to the paper feed direction, when the leading edge of the paper 1a reaches the paper feed roller 4 as shown in FIG. 4 is drawn into the sheet stacking section A. That is, in the state of FIG. 8, the sheet 1a is sent out from the slit 15 by the sending roller 8 on the one hand and pulled up by the paper feeding roller 4 on the other hand.

The sheet 1a delivered by the delivery roller 8 eventually comes out of the slit 15 as shown in FIG. Here, the paper feed amount until the paper 1a comes out of the slit 15 will be described with reference to FIG. In FIG. 13, the paper feed amount Q from the time when the paper conveyed leftward on the upper plates 5 and 6 passes through the print area Y to the time when the paper passes through the slit 15 is calculated as Q = d1 + inner circumference of the guide 11. + D2 + inner circumference of guide 13 (1), but in the present embodiment, Q = d1 + inner circumference of guide 11 + d2 + inner circumference of guide 13 + α (2).

When the feed motor 23 is composed of a step motor, the ASIC 21 rotates the feed motor 23 by the number of steps given in the above (2) from the time when the paper leaves the printing area Y. 22 is controlled. Here, α is a value corresponding to several steps, and the paper feed amount by the feed motor 23 is set to a value slightly larger than the calculated value of (1). In this way, the feed motor 23 is moved by a few more steps from the moment the sheet 1a comes out of the slit 15.
By rotating the paper 1a, the rear end of the paper 1a completely escapes from the slit 15, and at the time of this escape, the elasticity of the paper itself causes the rear end of the paper to curve toward the feed roller 9 side.

Then, the rotation direction of the feed motor 23 is switched to rotate the paper feed roller 4 in the paper feed direction as shown in FIG. 10, and the paper 1a is fed to the upper plate 5 by the paper feed roller 4. . At this time, the delivery roller 8 is rotating in the direction opposite to the paper feeding direction of the sheet 1a, but the dimensions are adjusted so that the sheet 1a does not hit the delivery roller 8. Further, the feed roller 9 is also rotating in the direction opposite to the paper feeding direction of the paper 1a, and the fed paper 1a is
Even in the skewed state, the posture is corrected by the feed roller 9.

Thereafter, the rotation direction of the feed motor 23 is switched, and the sheet 1a is conveyed while rotating the feed roller 9 and the sheet discharge roller 10 as shown in FIG. 11, and the sheet 1a is conveyed through the first conveying path. In the process, the printing unit 16 prints on the back surface of the sheet 1a. Further, the guide 11 is rotated by the motor 24 and is displaced to a position as shown in FIG. Then, the paper 1a for which double-sided printing has been completed is ejected by the paper ejection roller 10 as shown in FIG. 12, and the printing operation is completed.

FIG. 14 is a flow chart showing the operation described above, and schematically shows the procedure executed by the CPU 20 constituting the control section. When a print start command is received from a host device (not shown) such as a PC, it is first determined whether double-sided printing is to be performed (step S).
1). When double-sided printing is not performed (step S1; N
O), printing is performed on only one side (step S11), the paper is ejected (step S10), and the operation ends.

When performing double-sided printing (step S1; Y
ES), the guide 11 is raised as shown in FIG. 3 (step S2), and the printing unit 16 prints on the surface of the sheet 1a (step S3). Then, it is determined whether the paper 1a has left the print area Y (step S4). If the paper 1a has not left the print area Y, printing is continued (step S4; NO), and if the print area Y is left (step S4). ; YES), as described above, the feed motor 23 is driven by the number of steps obtained by adding α to the number of steps of the sheet 1a coming out of the slit 15 (step S5), and the sheet 1a is conveyed (FIGS. 4 to 6). Then, the sheet 1a is sent to the sheet stacking section A by the sending roller 8 and the sheet feeding roller 4 (step S
6, FIG. 7 to FIG. 9).

Next, the rotation direction of the paper feed roller 4 is switched, the paper 1a is sent to the first transport path (upper plates 5, 6), and the printing unit 16 prints on the back surface of the paper 1a (step S7). ~ S8, FIGS. 10 to 11). afterwards,
The guide 11 is tilted as shown in FIG. 11 (step S9), the double-sided printed sheet 1a is ejected by the ejection roller 10 (step S10), and the operation is completed.

[0021]

According to the present invention, since double-sided printing can be performed on paper without mounting a separate unit, the size of the printer does not become large and the installation space is small. Further, since the feed rollers of the first transport path and the second transport path are shared, the number of partial points can be saved and the transport mechanism can be simplified. Furthermore, the double-sided printing function can be realized by adding a slight configuration to the existing inkjet printer.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an inkjet printer according to the present invention.

FIG. 2 is a block diagram showing an electrical configuration of the printer.

FIG. 3 is an operation explanatory diagram when performing double-sided printing with a printer.

FIG. 4 is an operation explanatory diagram when performing double-sided printing with a printer.

FIG. 5 is an operation explanatory diagram when performing double-sided printing by the printer.

FIG. 6 is an operation explanatory diagram when performing double-sided printing by the printer.

FIG. 7 is an operation explanatory diagram when performing double-sided printing by the printer.

FIG. 8 is an operation explanatory diagram when performing double-sided printing by the printer.

FIG. 9 is an operation explanatory diagram when performing double-sided printing by the printer.

FIG. 10 is an operation explanatory diagram when double-sided printing is performed by the printer.

FIG. 11 is an operation explanatory diagram when performing double-sided printing by the printer.

FIG. 12 is an operation explanatory diagram when double-sided printing is performed by the printer.

FIG. 13 is a diagram illustrating a paper feed amount of paper.

FIG. 14 is a flowchart showing the operation of the printer.

[Explanation of symbols]

1,1a paper 4 paper feed rollers 5,6 Upper plate 7 Lower plate 8 Sending roller 9 Feed roller 10 Paper ejection roller 11,13,14 guide 15 slits 16 Printing section 20 CPU 23 Feed motor A paper stacking section Y print area

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Claims (6)

[Claims] 1. A paper feed roller for feeding the papers stacked in a paper stacking unit one by one; a first transport path for transporting the papers fed by the paper feed roller in a paper discharge direction; A printing unit that prints on the paper conveyed through the first conveyance path, and a discharge roller that is located at the discharge-side end of the first conveyance path and discharges the paper printed by the printing unit. In a printer having, a guide provided so as to be displaceable so as to face the paper discharge roller, and for a paper on which only the front surface is printed, the paper is turned upside down and the transport direction is opposite to the paper discharge direction. The first guide which allows the discharge of the sheet on which both sides are printed, and the sheet which is provided below the first conveying path and which is turned upside down by the first guide and is conveyed in the conveying direction. The second transport path for transporting the switched paper, and A feed roller that is provided in common to the first and second conveyance paths and that conveys the paper on the first conveyance path in the paper ejection direction and conveys the paper on the second conveyance path in the opposite direction to the paper ejection direction; A delivery roller for delivering the sheet that has been transported through the second transport path upward, and a sheet that is provided facing the delivery roller and that guides the sheet transported through the second transport path upward. A second guide, a third guide for switching the conveying direction of the sheet sent upward by the sending roller to the direction of the sheet feeding roller, and the surface is printed on the first carrying path during double-sided printing. The paper is guided to the second transport path via the first guide, and the paper whose transport direction is switched is guided to the paper stacking unit by the paper feed roller via the second and third guides, and then the paper feed roller. Change the rotation direction of And a control unit configured to perform a printing on the back surface by the printing unit and to discharge the paper on which both sides are printed by the paper discharge roller. Print printer. 2. A paper feed roller that feeds the papers stacked in the paper stacking unit one by one, and a first transport path that prints the papers fed by the paper feed roller and transports the papers in a paper discharge direction. In a printer provided with, a sheet provided on an end of a discharge side of the first transport path and printed only on a surface transported on the first transport path is turned upside down to set a transport direction as a discharge direction. A reversing means for switching to the opposite direction; a second conveying path for conveying the sheet whose conveyance direction has been switched by reversing the sheet by the reversing means; and a first conveying path that is commonly provided for the first and second conveying paths. And a feed roller that conveys the paper in the second conveyance path in the paper ejection direction and the paper in the second conveyance path in the opposite direction to the paper ejection direction, and sends the paper conveyed in the second conveyance path upward. And guiding means for guiding the paper to the paper stacking unit. At the time of printing, the sheet having the surface printed on the first transport path is guided to the second transport path by the reversing means, and also guided from the second transport path to the paper stacking section via the guide means, and then the paper is transferred to the first transport path. A double-sided printing printer, which is characterized in that it is sent to a conveyance path No. 1, printed on the back side, and ejects a sheet with both sides printed. 3. The double-sided printing printer according to claim 2, wherein the reversing means is provided at a paper discharge roller located at a paper discharge side end of the first transport path and facing the paper discharge roller. A double-sided printing printer, comprising: a first guide that reverses a sheet having a printed surface and switches a conveyance direction to a direction opposite to a sheet discharge direction. 4. The double-sided printing printer according to claim 2 or 3, wherein the guide means sends out a sheet that has been transported through the second transport path upward, and a transport roller. A second guide that is provided so as to face the roller and guides the sheet conveyed through the second conveying path upward; and a slit is formed between the delivery roller and the guide. A double-sided printing printer that features. 5. The double-sided printing printer according to claim 4, wherein after the sheet sent out from the slit is guided to the sheet stacking section by the sheet feeding roller, the rotation direction of the sheet feeding roller is switched to change the first sheet to the first sheet. A double-sided printing printer characterized in that it is sent to the transport path of the. 6. The double-sided printing printer according to claim 4 or 5, wherein the paper feed amount from when the paper passes through the print area of the first transport path to when it exits the slit is more than the calculated value. A double-sided printing printer characterized by being set to a slightly larger value.