JPH05155098A - Printer - Google Patents

Abstract

PURPOSE:To prevent a stained recording paper or jamming from generating by a method wherein an envelope is identified by the combination of recording paper detection by a pair of recording paper detecting sensors which are provided at a recording paper passing area, and when a printing is done on an envelope, the gap between paper and the printing head is adjusted to an appropriate quantity so that paper can pass through the gap. CONSTITUTION:When a recording paper is set on a cut form table, if both single form detecting sensors 16, 17 detected the recording paper, it is decided that the recording paper is a normal paper, and a gap between the recording paper and a paper guide for an automatic paper thickness adjustment is ensured to be approximately the thickness of one sheet of the recording paper. In the meantime, when an envelope 22 is set, since the cut form detecting sensor 16 does not detect a recording paper because of a notch at the wrap part 22a of the envelope 222, it is recognized that the recording paper is an envelope. The automatic paper thickness adjustment is performed at an area of the envelope which is not pasted, but the thickness are different at each pasted area. When it is decided that the envelope 22 is set, the quantity, by which a supporting rail is rotated in the reverse direction from a condition in which the paper guide is in contact with the recording paper, is increased than a normal recording paper by an appropriate quantity, by the automatic paper thickness adjustment, and the gap between the recording paper and paper guide is made to be a quantity through which a pasted area 22e can pass.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer, and more particularly to an automatic paper thickness adjusting system capable of printing on an envelope having a non-uniform thickness.

[0002]

2. Description of the Related Art As described in Japanese Utility Model Publication No. 63-48586, a conventional device is provided with a detection sensor for detecting the leading edge of a paper sheet, the position of the paper sheet, the presence / absence of the paper sheet, and the skew of the paper sheet. It was usual to detect only the feed. That is,
There are a method of detecting a set sheet and then conveying the sheet by a predetermined amount to a predetermined position for printing, and a method of detecting that the sheet is set obliquely by a pair of detection sensors.

In a printer having an automatic paper thickness adjusting mechanism,
The paper detection sensor detects that the paper has been set, and after feeding a predetermined amount of paper to the printing location, automatic paper thickness adjustment is performed to ensure a proper gap between the print head and the paper before printing. The position of the paper for which the paper thickness is adjusted is normally set at a specific position, and is often set at the upper left portion of the paper. In the wire dot printer, the gap between the print head and the paper needs to be narrowed in order to shorten the operation time of the wire as the print head becomes faster.
The gap is about 3 sheets of paper (55 kg continuous paper). An ink ribbon is provided at the tip of the print head, and the gap between the ink ribbon and the paper is usually about one sheet. In addition, a paper guide is provided near the print head to prevent the ink ribbon and paper from contacting each other.
Paper) About one sheet.

Further, in order to shorten the print output processing time, the paper thickness is not adjusted plural times, such as by adjusting the paper thickness line by line for one sheet, and the paper is adjusted only once. It is usual to adjust the thickness.

[0005]

The above-mentioned prior art is premised on that the thickness of the paper is uniform. In a printer having an automatic paper thickness adjusting mechanism, the paper portion for paper thickness adjustment is If there are different thickness parts on one sheet of paper, there is a place on the one sheet where the gap between the print head and the paper cannot be secured, so there is a gap between the print head and the sheet. If the amount is smaller than the proper amount, a paper jam may occur, or an ink ribbon provided at the tip of the print head may come into contact with the paper, causing problems such as soiling of the paper.
Also, if the gap between the print head and the paper becomes wider than the appropriate amount,
Since the wire of the print head does not sufficiently hit the paper and an appropriate impact force cannot be obtained, problems such as thin printing occur.

[0006] For example, in an envelope or the like, the glued portion has one or three sheets of paper superposed over the portion other than the glued portion. For this reason, when printing an envelope with a printer having an automatic paper thickness adjustment mechanism, the paper is adjusted after the paper thickness is adjusted at a portion other than the glue portion, so that the glue portion passes through the print head portion. At this time, the gluing part comes into contact with the ink ribbon or the paper guide near the print head. as a result,
Since there is no gap between the print head and the paper guide near the print head that passes through the glue part, paper jams may occur,
Problems such as paper stains occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a printer having good print quality, which does not cause paper jams, paper stains, print smearing, etc. even on paper such as envelopes having a non-uniform thickness.

[0008]

The above object is to provide a pair of paper detection sensors in a paper passage portion, identify an envelope by a combination of presence or absence of paper detection of the paper detection sensor, and to print on the envelope, This is achieved by automatically adjusting the paper thickness so as to secure a gap between the print head and the envelope in an appropriate amount that allows the glued portion of the envelope to pass through.

[0009]

When a sheet is set, when a pair of sheet detection sensors provided in the sheet passage section detect both sheets, it is determined that the sheet is a normal sheet.
When the paper detection sensor provided at the left end of one paper does not detect the paper and the paper detection sensor provided at the center of the other paper detects the paper, it recognizes that the envelope has been set. When it is recognized as an envelope, the automatic paper thickness adjustment mechanism causes the gap between the envelope and the print head to pass through the gap between the envelope and the print head, so that the overlapped portion of the glue part of the envelope can also pass through the print head. Set so that a gap larger than the gap of can be secured. As a result, even when the envelope is printed, it is possible to prevent the paper from sticking to the ink ribbon and contaminating the paper at the overlapped portion of the paper. It is possible to secure a gap through which the gluing part can pass and prevent the occurrence of paper jam.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The print head 1 is fixed to the carrier 2,
It is supported by the support rails 3 and 4, and has a structure that is movable left and right. The paper feed roller 12 is pinched by the pressing roller 11, and the pair of paper feed roller 12 and the pressing roller 1
1 are arranged in front of and behind the print head 1. The sheet is set on the single-cut sheet table 10, and the sheet is fed to the platen 8 by the sandwiching force of the sheet feed roller 12 and the pressing roller 11 for printing. Paper detection sensors 16, 17, and 18 are provided in front of and behind the paper feed roller 12, and the single-cut detection sensor 16 is provided.
And 17 identify the envelope from the normal paper, and the single-sheet detection sensor 18 monitors the leading edge of the paper to provide a reference position for the paper position.

When the paper is set, the single-cut detection sensor 1
A sheet is detected at 6 and 17, and the sheet feed roller 12 is driven to pull in the sheet. When the paper is sent to the paper detection sensor 18, the paper detection sensor 18 detects the paper, and a predetermined amount of paper is sent based on the position, and the paper is fed to the platen 8.
And passes through the sheet and stops at the predetermined print position on the sheet. In this state, the automatic paper thickness adjusting motor 20 is driven and the support rail 3 is rotated. Both ends 3a and 3b of the support rail 3 are eccentric, and the carrier 2 moves up and down as the support rail 3 rotates. The carrier 2 is lowered by the drive of the automatic paper thickness adjustment motor 20, the paper guide 19 of the print head unit comes into contact with the paper, and the contact is detected, and the drive of the automatic paper thickness adjustment motor 20 is stopped. To do. From this state, the support rail 3 is rotated in the opposite direction to raise the carrier 2 by a predetermined amount to secure a gap between the paper guide 19 and the paper. After that, the printing is performed, and after the printing is completed, the paper feed roller 12 is rotated in the reverse direction to eject the paper to the single-cut table 10, and the print output process is completed.

When a sheet is set on the sheet table 10 and both sheet detection sensors 16 and 17 detect the sheet, it is determined that the sheet is a normal sheet, and the sheet in the automatic sheet thickness adjustment described above. A gap of the guide 19 is secured about one sheet. On the other hand, when the envelope 22 is set, the cut sheet detection sensor 16 is cut by the cutout portion of the flap portion 22a of the envelope.
Since it does not detect paper, it can be recognized as an envelope. The thickness of the envelope 22 varies depending on the location where the glue is applied, and two non-glued portions 22b and glued portions 22c, 2 are provided.
2d and 22e have a form in which three sheets, three sheets, and four sheets are stacked, respectively. For automatic paper thickness adjustment, the part without glue 22
Since it is performed in step b, if the gap between the sheet and the sheet guide 19 is set to about one sheet as in the case of normal sheets, the gluing parts 22c, 22c
d and 22e cannot pass between the paper guide 19 and the platen 8. Therefore, when it is determined that the envelope is set, the paper guide 19 is operated by the automatic paper thickness adjustment operation.
The amount by which the support rail 3 is rotated in the reverse direction from the position where the paper comes into contact with the paper is increased by an appropriate amount compared to the normal paper, so that the gluing part 22e can pass through the gap between the paper and the paper guide 19. can do.

The separation between the envelope and the normal paper is determined by whether or not the single-cut detection sensor 16 detects the paper. Even with normal paper, if the paper is set at a distance from the left edge guide 23 of the paper, the single-cut is detected. The detection sensor 16 does not detect the paper,
The single-cut detection sensor 17 detects a sheet, and it is possible that the single-cut detection sensor 17 erroneously detects that an envelope is set. For this reason, in order to normally set the paper and separate the envelope, when the required amount of the paper is fed, if the single-cut detection sensor 16 detects the paper, the envelope and the paper are detected if the paper is not detected. By determining a set mistake, erroneous detection can be prevented.

According to the present embodiment, the paper detection sensors are provided at the left end and the center of the paper, and the combination of the presence or absence of the paper of the two sensors makes it possible to separate the envelope from the normal paper.
When printing on envelopes, you can set the gap between the paper and the print head or the gap between the paper and the paper guide by a predetermined amount more than normal paper, and the glue part of the envelope where the paper overlaps A gap between the print head and the paper guide near the print head can be secured. As a result, it is possible to print on a sheet of paper with an uneven thickness, such as an envelope, and stains due to contact of the envelope glued part with the ink ribbon, and paper caused by contact of the print head part and the paper guide with the envelope glued part Jam can be prevented.

[0015]

According to the present invention, a pair of paper detection sensors provided in the paper passage portion can separate an envelope from a normal paper. Therefore, when printing on the envelope, a gap between the paper and the print head is not provided. It can be set by automatic paper thickness adjustment to an appropriate amount that allows the envelope to pass, the glue part of the envelope comes into contact with the ink ribbon to generate dirt, and the glue part of the envelope cannot pass through the print head part, causing paper jams. It is possible to print envelopes without doing this.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

3 is an overall perspective view of FIG.

[Explanation of symbols]

1 ... Print head, 2 ... Carrier, 3 ... Support rail, 8 ...
Platen, 11 ... pressing roller, 12 ... paper feed roller,
16, 17, 18 ... Paper detection sensor, 19 ... Paper guide, 20 ... Automatic paper thickness adjusting motor, 23 ... Paper left edge guide.

Claims (1)

[Claims] 1. A print head, a pair of paper feed rollers provided in front of and behind the print head, and a platen for supporting the paper. The gap between the paper and the print head is automatically adjusted according to the thickness of the paper. In a printer equipped with a mechanism for providing a pair of paper detection sensors in the paper passage section, the envelope is identified by a combination of the presence or absence of paper detection of the paper detection sensor,
A printer characterized in that, when printing on an envelope, the paper thickness is automatically adjusted so that a gap between the print head and the envelope can be secured in an appropriate amount so that the envelope can pass through.