JPH06127052A - Printer - Google Patents

Abstract

PURPOSE:To print characters on both surfaces of paper without setting the surface and rear of paper by an operator in a printer such as a dot printer. CONSTITUTION:Paper feed means respectively consisting of first and second printing paper guide members 3, 9, follower rollers 4, 10 for pressing printing paper to a cylindrical platen 2 and first and second paper detection means 5, 11 for detecting the printing paper are provided above and under the platen of a dot printer. A paper feed route changeover means 17 for changing over the upper and lower paper feed means in order to feed the printing paper and a paper feed roller 12 for feeding the paper to the upstream side of the paper feed changeover means are provided on the upstream side of the paper feed means and the changeover of the paper feed route changeover means is controlled by a paper feed route changeover control means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing device.

[0002]

2. Description of the Related Art In recent years, with the spread of word processors, the frequency of printing on cut sheets of printers has increased. In addition, the need for double-sided printing of documents is increasing due to the lack of paper resources and space.

A conventional printing device will be described below.
FIG. 4 is a side view of a conventional printing apparatus. 41 is a cut sheet fed from the rear, 42 is a platen, 43 is a paper guide member for guiding the cut sheet 41 along the platen 42, and 44 is a cut sheet. A roller for pressing the paper sheet 41 against the platen 42, a paper detection unit 45 for detecting the presence or absence of a single paper sheet, and a print head 46. Reference numeral 47 is a carriage for mounting a print head, and 48 is a tractor for transporting continuous paper.

The printing operation of the conventional printing apparatus constructed as described above will be described below. When printing on a cut sheet as shown in FIG. 4, the cut sheet 41 is a paper guide member 43.
Printing is performed by the print head 46 while being conveyed by the platen 42 and the roller 44 along.

[0005]

However, in the above-mentioned conventional configuration, in order to print on both the front and back sides of the cut sheet, the operator once manually takes out the cut sheet and prints it on both sides. It was necessary to change the orientation, set the cut sheets again, and then start printing on the back side. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a printing apparatus that can automatically switch the front and back of cut sheets and reduce the labor of the operator.

[0006]

In order to achieve the above-mentioned object, a printer according to the present invention has a first plate below a cylindrical platen.
A first sheet conveying means including a sheet guiding member and a roller pressed against the platen; a second sheet conveying means including a second sheet guiding member and a roller pressed against the platen above the platen; and the first sheet conveying means And a paper transport path switching means provided behind the second paper transport means (on the side of the paper transport roller), a paper transport path switching control means for controlling the switching operation of the paper transport path switching means, and the paper transport path switch A paper transport roller located behind the unit (on the side of the cut sheet) for transporting the paper, a first paper detection unit provided in the paper path of the first paper transport unit, and a paper path of the second paper transport unit. The second sheet detecting means is provided therein.

[0007]

According to the present invention having the above-described structure, after the front surface of the cut sheet is printed by using the first sheet conveying means, the leading edge of the cut sheet is returned to the rear of the sheet conveying path switching means, and then the sheet conveying path switching means is used to convey the sheet. Switching by the route switching control means, then the second
By automatically printing the back side of the cut sheet by using the sheet conveying means, the operator can print the front and back sides of the cut sheet without manually resetting the front and back sides of the cut sheet.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a cross section of the printer. In FIG. 1, 1 is a cut sheet, 2 is a platen, 3 is a first paper guide member, 4 is a driven roller which is pressed against the platen 2 by a spring 14 and is driven by 5,
The sheet detecting means, which is a first sheet conveying means, has a first sheet guiding member 3, a driven roller 4, and a first sheet detecting means. 6 is a print head, 7 is a carriage, 9 is a second paper guide member, 10 is a driven roller which is pressed against the platen 2 by a spring 15 and is driven, 11 is a second paper detecting means, and the second paper conveying means is a second paper detecting means. It has two paper guide members 9, a driven roller 10 and a second paper detecting means 11. 12 is a paper transport roller that transports the cut sheet 1, 13 is a driven roller that is pressed by the spring 16 and is driven by the paper transport roller 12,
Reference numeral 17 denotes a paper transport path switching means which is driven by an actuator 18 and switches the transport path of the cut-sheet paper 1 up and down at the time of paper feeding.

FIG. 2 is a functional block diagram of the printing apparatus according to the embodiment of the present invention. In FIG. 2, the CPU 19 receives paper presence / absence information from the first paper presence / absence determining means 25 and the second paper presence / absence determining means 26, and controls the platen control means 20, the paper transport path switching control means 22, and the paper transport roller control means 23. . The platen 2 is rotated by the power of the platen drive means 21 driven by the control of the platen control means 20. The paper transport path switching means 17 performs the paper transport path switching operation by the power of the actuator 18 driven by the control of the paper transport path switching control means 22. The paper carrying roller 12 is rotated by the power of the paper carrying roller driving means 24 driven by the control of the paper carrying roller control means 23. The first sheet presence / absence determining unit 25 determines the presence / absence of a sheet based on a signal from the first sheet detecting unit 5, and sends the information to the CPU 19. The second sheet presence / absence determining means 26 determines the presence / absence of a sheet based on a signal from the second sheet detecting means 11 and outputs the information as C
Send to PU19.

The operation of the printing apparatus of this embodiment constructed as described above will be described below with reference to the flow chart of FIG. 3 and FIGS. When a paper feed command switch of the printer or a paper feed command is input from the computer, the paper transport roller 12 and the platen 2 are rotated in the forward direction (X direction) in step 1 (denoted as S _{1 in the} drawings; the same applies hereinafter). To do. Here, the cut sheet 1 is conveyed downward to the platen 2 along the sheet conveyance path switching means 17 set on the side of the first sheet conveyance means (direction A). Cut sheet 1 is step 2
Then, the sheet is conveyed by the sheet conveying roller 12 and the platen 2 until the first sheet detecting means 5 detects the presence of the sheet (A
direction). After the detection, in step 3, the print head 6 further conveys a predetermined amount to a printable position (direction A), and in step 4
Then, the front side of the cut sheet 1 is printed by the print head 6 while being further conveyed (direction A).

Next, at step 5, when the first sheet detecting means 5 detects the cut sheet 1, the front side printing of the cut sheet 1 is finished,
In step 6, the paper transport roller 12 and the platen 2 are reversely driven (Y direction), and in step 7, the cut paper 1 is transported by a predetermined amount to a position where the first paper detection means 5 detects the presence of paper. In the B direction), the cut sheet 1 is further conveyed until the first sheet detecting unit 5 detects that there is no sheet in step 8 (B direction).

Next, in step 9, the cut sheet 1 is further conveyed until the leading edge of the cut sheet 1 is located between the sheet conveying path switching means 17 and the sheet conveying roller 12 (direction B). In step 10, the sheet conveying path switching means 17 is switched to the second sheet conveying means side by the actuator 18. Next, in step 11, the paper transport roller 12 is driven in the normal direction (direction A) and the platen 2 is driven in the reverse direction.
(Y direction), the second sheet detecting means 11 conveys the cut sheet 1 to the second sheet conveying means side above the platen 2 until the second sheet detecting means 11 detects the presence of the sheet (A direction), and the step 13 Then, the print head 6 further conveys it to a printable position (direction A).

Next, in step 14, the sheet conveying roller 12 and the platen 2 convey the cut sheet 1 (direction A) until the second sheet detecting means 11 detects the absence of sheet in step 15. The back side of the cut-sheet paper 1 is printed at step 6. Next, at step 16, the sheet conveying path switching means 17 is switched to the first sheet conveying means side, and at step 17, the cut sheet 1 is conveyed by a predetermined amount (direction A) and the cut sheet is discharged.

[0014]

As is apparent from the above embodiments, the present invention is provided with a pair of sheet conveying means provided above and below the platen, a sheet conveying path switching means, and a sheet conveying means for each conveying path. Thus, there is an effect that it is possible to provide a printing device that enables the operator to automatically print the front and back sides of a sheet without manually resetting the front and back sides of the cut sheet.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a printer according to an embodiment of the present invention ((a) a state before starting feeding, (b) a state when printing on the front surface of a cut sheet, and (c) a state when printing on the back side of the cut sheet. State).

FIG. 2 is a block diagram showing a function of a paper feeding portion of the printing apparatus according to the embodiment of the present invention.

FIG. 3 is a flowchart showing a paper feeding operation of the printing apparatus according to the embodiment of the present invention.

FIG. 4 is a side view of a conventional printing device.

[Explanation of symbols]

1, 41 ... Single-cut paper, 2, 42 ... Platen, 3 ... First paper guide member, 4, 10, 13 ... Followed roller, 5 ... First paper detecting means, 6, 46 ... Print head, 7, 47 ... Carriage, 9 ... Second paper guide member, 11 ... Second paper detecting means, 12 ... Paper carrying roller, 14, 15, 16 ... Spring, 17 ... Paper carrying path switching means, 18 ... Actuator, 19 ... CPU, 20 ... Platen control means, 21 ... Platen drive means, 22 ... Paper transport path switching control means,
23 ... Paper transport roller control means, 24 ... Paper transport roller driving means, 25 ... First paper presence determination means, 26 ... Second paper presence determination means, 43 ... Paper guide member, 44 ... Roller, 45 ... Paper detection means, 48 ... tractor.

Claims (3)

[Claims] 1. A first sheet conveying means including a first sheet guide member and a roller pressed against the platen below a cylindrical platen, and a second sheet guide member and a roller pressed against the platen above the platen. A second sheet conveying means provided, and a sheet conveying path located behind the first sheet conveying means and the second sheet conveying means (on the side of the sheet conveying roller) and having a sheet conveying path on the side of the first sheet conveying means and the second sheet conveying means. Paper transport path switching means for switching to any of the means side, paper transport path switching control means for controlling the switching operation of the paper transport path switching means, and the rear of the paper transport path switching means (cut sheet side) And a paper transporting roller for transporting the paper. 2. The printer according to claim 1, wherein the paper transport path switching means is rotated about an fulcrum by an actuator. 3. A first sheet detecting means provided in a sheet path of the first sheet conveying means, and a second sheet detecting means in a sheet path of the second sheet conveying means. The printing device according to claim 1 or 2.