JPH0684087B2 - Paper feeding method in printer - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing paper feeding method in a printer of an information processing system, in which the leading end of the fed printing paper is used as a paper guide on the paper ejection side. The present invention relates to a paper feeding method for smoothly receiving paper.

-Summary of the Invention-The present invention relates to a printer device in which a paper path near a printing unit is formed in a substantially straight line until the leading edge of the printing paper passes through the printing unit and is received by a paper feed roller on the paper discharge side. The paper feed is performed by separating the platen from the normal position of the print head at the time of a line feed operation between them. By performing the method of the present invention, the platen is slightly projected from the paper path to perform printing. As a result, it is possible to reduce the print noise and prevent the bending of the paper and the jam of the paper that occur at the contact portion between the leading edge of the paper and the paper guide on the discharge side, especially when thin paper is used as the printing paper. is there.

-Prior Art-A printer device in which paper feed rollers are arranged on both sides of a printing unit formed between a platen and a print head, and paper passages between the paper feed rollers on both sides are formed in a substantially straight line is a continuous printer. Print processing and conversion of both form paper and single-cut paper can be performed easily, and printing quality and line feed accuracy do not change due to differences in the thickness and rigidity of printing paper, and uniform and high-quality printing can be performed on various types of paper. It has the feature that it can be performed.

However, in the printer device having the above structure, the adhesion between the platen and the printing paper is lower than that in the printer device in which the paper is wound around the platen, so there is a problem that noise during printing becomes high. In order to avoid this, the platen may have a structure in which the platen is slightly projected toward the print head from the surface connecting the paper sandwiching lines of the paper feed rollers on both sides.

-Problems to be Solved by the Invention- In a printer, there is a demand to make a non-printable area on a sheet as small as possible, and also to print with a small upper margin. If you try to print with a small top margin on the printer device with the above structure,
Inevitably, printing is inevitably performed with the paper being held only by the paper feed rollers on the paper feed side.

However, when the structure in which the platen is projected to the print head side is adopted as described above, as shown in FIG. 3, the paper 1 is fed by the paper feed roller 2 in order to reduce the upper margin.
When printing is carried out only when the paper is pinched, and when the line feed operation that follows is performed, the paper 1 bends upward due to the projection of the platen 5, and when the paper leading edge 1a collides with the paper guide 8 on the paper ejection side, the paper If the guide 8 does not guide the leading edge of the sheet smoothly, the leading edge of the sheet may be bent or a sheet jam may occur. In particular, when the paper 1 is a thin paper, or when the feeding amount of the paper 1 is large and the feeding speed is high, such an obstacle is likely to occur.

The present invention has an object to avoid the above problems, and provides a paper feeding method by which the leading end of the paper 1 can be smoothly received by the paper guide 8 or the paper feed roller 3 on the paper discharge side. It is an object of the present invention to provide a printer device that can avoid the bending of a sheet and the jam of a sheet and can print with a low print noise and a small upper margin without any trouble.

-Means for Solving Problems-In the present invention, when a paper feed command is given,
First, a judgment procedure is executed to judge whether or not the leading edge of the paper may pass the print head side end of the paper guide when the paper is fed, and when it cannot pass, the procedure is continued. Paper feeding is performed by a method of feeding the paper, separating the platen from the print head when possible, and then returning the platen to its normal position.

In the above method, it is determined whether the leading edge of the sheet may pass the edge of the sheet guide or not when the commanded sheet feeding is performed. In addition to the method of directly determining the above, it can be performed by, for example, determining whether or not the paper 1 is already caught in the paper feed roller 3 on the paper discharge side.

That is, if the paper 1 is caught in the paper feed roller 3 on the paper discharge side, the situation in which the front end of the paper passes the end of the paper guide cannot occur when the paper is fed. Paper feeding is performed with 5 being projected. When the paper 1 is not caught in the paper feed roller 3 on the paper discharge side, the front end of the paper may pass through the end of the paper guide during the paper feeding. At that time, the platen 5 is temporarily separated. And feed the paper.

The paper feeding method of the present invention may be carried out only when the paper 1 is thinner than a preset paper thickness. When the paper is fed while being separated from the platen 5, when the paper leading edge 1a is to be pinched by the paper feeding roller 3 on the paper discharge side during the line feed operation, it is preferable that the paper leading edge 1a be the paper feeding roller 3. A method of returning the platen 5 to the normal position immediately before being clamped by the is adopted.

-Operation- According to the above method, since the platen 5 is separated downward as shown by the solid line in FIG. 2 when the leading end 1a of the sheet 1 to be fed comes into contact with the sheet guide 8 on the sheet discharge side, Paper 1
Is in a state in which it extends straight from the roller 2 on the paper feed side through the upper surface of the platen 5 to the roller 3 on the paper discharge side, and the leading edge 1a of the paper is smoothly guided by the paper guides 8 and 9 on the paper discharge side. It is fed into the nip portion 3a of the roller 3 on the paper side.

In the present invention, the retracting and returning operations of the platen are performed at the time of feeding the paper because the paper is fed to the paper feeding roller 3 on the paper discharging side to the maximum extent.
Since the sheet is caught in the sheet, it is seldom occupied in the feeding operation of the entire sheet, and therefore the reduction of the sheet throughput due to the retracting and returning operations of the platen can be minimized.

When the paper 1 is thin, a procedure for separating the platen 5 is particularly necessary. When the paper 1 is thick, the paper leading edge 1a collides with the paper guide 8 at a relatively large angle as shown in FIG. This is because the rigidity of the sheet guides the tip without bending. Since the time required for separating the platen 5 can be set to about 0.1 seconds, the decrease in the throughput due to the separating operation of the platen 5 is slight, but the separating operation of the platen 5 should be performed especially when the paper throughput is taken into consideration. The platen 5 may be separated only in the minimum necessary case, that is, only when the paper is thin and the leading edge of the paper comes into contact with the paper guide 8.

Further, if the platen 5 is to be returned just before the nipping at the time of line feed where the leading edge of the paper is nipped by the paper feed roller 3 on the paper discharge side, the platen 5 is returned with both sides of the paper being nipped. It is possible to avoid the risk that the sheet slips at the nip portion of the roller 2 or 3 due to the tension applied to the sheet when the sheet is pulled and the line feed dimension is slightly misaligned.

-Embodiment- FIG. 2 is a side view showing an example of the structure of a printer in which the method of the present invention is carried out, and has a structure for detecting the thickness of the inserted sheet 1 by raising and lowering the platen. .

In the drawing, the same members as those in FIG. 3 are designated by the same reference numerals, and the platen 5 is attached to the tip of the arm 11 pivotally supported by the drive roller shaft 26 of the paper feed roller 2 and is vertically movable. Yes,
The carrier 12 that supports the print head 4 has its guide rod.
The print head 4 can be raised and lowered by being freely rotated around 13.

14 is an upper guide which is paired with the guide rod 13 and is a carrier.
An L-shaped frame 15 is fixed to the upper end of 12, a guide roller 16 is pivotally attached to the L-shaped frame, and a shoe 17 urged toward the peripheral surface of the guide roller 16 is provided. The upper guide 14 is sandwiched by a guide roller 16 and a shoe 17, and the rotation position of the carrier 12 around the guide rod 13 is determined.

Reference numeral 18 is a plate piece extending from the L-shaped frame 15, and 19 is a photoelectric sensor mounted on an immovable member, which detects the entrance of the plate piece 18 by the rotation of the carrier 12 around the guide rod 13.

Reference numeral 21 denotes a cam shaft which is parallel to the platen 5 and is axially mounted below the platen 5. The cams 22 are fixed to both sides of the cam shaft 21.
The peripheral surface of 22 is in contact with the outer ring of the ball bearing 23 fitted on both sides of the platen 5.

24 is a gear fixed to the cam shaft 21, 25 is a gear meshing with the gear 24, and the gear 25 is fixed to the output shaft of a pulse motor (not shown).

Before describing the method of the present invention, a method of detecting the paper thickness of the paper 1 in the apparatus having the structure shown in FIG. 2 will be described. When the cam 22 is rotated in the direction of arrow A in the figure with the head 1 inserted and inserted between the print head 4 and the platen 5 of the paper 1,
The platen 5 rises and pushes up the print head 4 via the paper 1. Then, the shoe 17 retracts, and the carrier 12 rotates in the direction of arrow C in the figure. Then, by detecting the rotation amount of the cam shaft 21 when the tip of the plate piece 18 is detected by the photoelectric sensor 19, that is, the number of pulses given to the pulse motor for rotating the cam shaft 21, the thickness of the paper 1 is detected. Is detected.
Therefore, the cam 23 is rotated in the direction of the arrow B this time, and the paper 1
The platen 5 is set at a normal position shown by an imaginary line in FIG. 2 so that an optimum head gap corresponding to the thickness of the platen is formed. At the regular printing position, the upper end of the platen 5 projects from the surface connecting the nibs 2a and 3a of the paper feed rollers 2 and 3 for the reason described above, and the projection height is about 1 mm. The execution of the automatic head gap in step 41 in the flowchart of FIG. 1 indicates the paper thickness detection operation according to the above procedure.

After this paper thickness detection is performed, the line feed operation according to the method of the present invention is performed in the procedure shown in step 42 onward in FIG.

First, it is determined whether the inserted paper 1 is thick paper or thin paper, and if it is thick paper, a normal process is performed so that the platen 5 is not separated when the paper is fed. The judgment of thick paper or thin paper may be made by registering the judgment data in advance and comparing it with the paper thickness detected in step 41. If the sheet 1 is a thin sheet, it is judged whether the given command is a line feed or a discharge command (step 43), and if neither (for example, a print command), the command is executed as it is. If the given command is a line feed command or a discharge command, it is determined whether the paper is already nipped by the paper feed roller 3 on the paper discharge side (step 44). This determination is made by monitoring the cumulative feed amount of the sheet 1 from the position of the cue. If the sheet 1 has already been sandwiched by the rollers 3 on the sheet discharge side, there is no possibility that the sheet leading edge 1a will collide with the sheet guide 8. Therefore, the normal processing for feeding the sheet with the platen 5 kept at the fixed position. Is executed.

If the paper 1 is not pinched by the paper feed roller 3 on the paper discharge side, a lowering operation for separating the platen 5 to the position indicated by the solid line in FIG. 2 is performed in step 45. Then, it is determined whether or not the paper 1 is caught in the paper feed roller 3 on the paper discharge side during the execution of the commanded line feed operation (step 4).
6) If it is not bitten, a line feed operation is performed with the platen 5 being lowered (step 47), and the platen 5 after line feed is performed.
Are restored (step 48). Further, when the sheet 1 is caught in the sheet discharge side roller 3 during the line feed, the sheet 1 is fed immediately before the sheet discharge side roller 3 with the platen 5 lowered (step 49), and the platen 5 is fed. Is returned (step 50), and a line feed for the remaining word amount is performed (step 50).
51).

Instead of determining whether the paper 1 is nipped by the roller 3 on the paper discharge side in step 44, the leading end of the paper 1 reaches the leading end position of the paper guide 8 during the execution of the instructed line feed or discharging operation. It may be determined whether or not the platen down and the normal process may be switched. Further, when the inserted paper has a downward curl at the tip, even if the paper is thin paper, the line feed operation may be performed in the normal process without the judgment of step 42 even if the paper is thin. If necessary, it is also possible to provide a selection branch of moving the platen 5 upward, that is, in the direction close to the print head 4 in accordance with the winding direction of the leading edge of the paper to execute the line feed or discharge operation. .

-Effects of the Invention-According to the method of the present invention, it is possible to avoid an obstacle that occurs when the leading edge of the paper comes into contact with the paper guide on the paper discharge side when the paper is line-fed, and it is possible to prevent the thickness of the paper from changing. Regardless of the situation, it is possible to perform a reliable line feed operation.
As a result, the printer can be arranged so as to project toward the print head, and it is possible to provide a printer device with low printing sound and capable of printing immediately after the upper edge of the paper.

[Brief description of drawings]

FIG. 1 is a flow chart showing an embodiment of the method of the present invention, FIG. 2 is a side view showing an example of the structure of a printer apparatus for carrying out the method of the present invention, and FIG. 3 is a side view of a printer apparatus having a conventional structure. . In the figure, 1: Paper, 2, 3: Paper feed roller 4: Print head, 5: Platen 8, 9: Paper guide, 22: Cam 23: Ball bearing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-53-140111 (JP, A) SAI 55-13048 (JP, U)

Claims (3)

[Claims] 1. A paper feed roller is arranged on both sides of a printing unit formed between a platen and a print head, and a paper path between the paper feed rollers on both sides is formed in a substantially straight line.
A paper guide is arranged between the paper feed roller on the paper discharge side and the printing unit, and the platen projects slightly toward the print head from the surface connecting the paper sandwiching lines of the paper feed rollers on both sides. In the feeding method, when a paper feeding command is given, first, it is determined whether or not the leading edge of the paper may pass the print head side end portion of the paper guide when the paper feeding is performed. When the procedure is executed, the paper is fed as it is when it cannot be passed, and when it is possible, the platen is separated from the print head and the paper is fed, and then the platen is returned to its normal position. Paper feeding method in printer device. 2. When the platen is separated from the print head and the paper is fed, it is determined whether or not the leading edge of the paper reaches the position of the paper feed roller on the paper discharge side during the feeding of the commanded amount. If it does not reach, the paper feed is performed by the commanded amount, and when it reaches, the paper is fed until just before the leading edge of the paper reaches the position of the paper feed roller on the paper discharge side, and the paper feed operation is temporarily stopped. Characterized in that the separated platen is returned to a regular position and then the remaining paper is fed.
The paper feeding method according to claim 1. 3. A paper thickness detecting procedure of a paper is executed prior to the paper feeding method, and the method according to claim 1 or 2 is executed when the paper thickness is smaller than a set value. A paper feeding method characterized in that