EP-4737366-A1 - PRINTER

EP4737366A1EP 4737366 A1EP4737366 A1EP 4737366A1EP-4737366-A1

Abstract

In order to prevent a feed direction of a paper from significantly varying due to swinging of a retard roller within an allowable range of an insertion depth of a paper tray relative to main body of a printer, a printer (100) a pickup roller (81) and a feed roller (82) fixed to a main body, a paper tray that is detachably attached, and a retard roller (84) that contacts the feed roller (82) and carries the housed paper (S) by sandwiching with the feed roller (82) when the paper tray (20) is attached, wherein the retard roller (84) includes a base member (84d) fixed to a lower portion of a front portion of the paper tray (20), a roller member (84b) that contacts the feed roller (82), and a swinging arm member (84a) that rotatably supports the roller member (84b) at an upper end portion, has a lower end portion provided to be rotatable forward and backward relative to the base member (84d), is disposed to extend in a height direction (H), and swings forward by the roller member (84b) pressed by the feed roller (82).

Inventors

INOKUCHI, YUTAKA

Assignees

Citizen Systems Japan CO., LTD.

Dates

Publication Date: 20260506
Application Date: 20240520

Claims (6)

A printer comprising: a feed roller fixed to a main body of the printer; a paper tray that is detachably attached to the main body of the printer and houses many sheets; and a retard roller that contacts the feed roller and carries the paper housed in the paper tray by sandwiching the paper with the feed roller when the paper tray is attached to the main body of the printer, wherein the retard roller includes a base member fixed to a lower portion of a front portion of the paper tray, a roller member that contacts the feed roller, and a swinging arm member that rotatably supports the roller member at an upper end portion, has a lower end portion provided to be rotatable forward and backward relative to the base member, is disposed to extend in a height direction, and swings forward when the roller member contacts the feed roller.
The printer according to claim 1, comprising a coil spring that presses the swinging arm member backward within a rotatable range to be swingable forward within the rotatable range when the roller member is pressed forward by the feed roller.
The printer according to claim 1 or 2, wherein the roller member is set such that a reverse torque in a reverse direction when feeding the paper in the reverse direction is smaller than a reverse torque in a forward rotation direction when feeding the paper in a forward direction.
The printer according to claim 1 or 2, wherein the retard roller contacts the feed roller through an opening formed in an inclined plate having a backwardly sloping inclination at a front portion of the paper tray.
The printer according to claim 1 or 2, comprising a paper guide that is provided in the main body of the printer, and is disposed above the front of the paper tray when the paper tray is attached to the main body of the printer, wherein a portion of the inclined plate of the paper tray in a width direction is recessed forward and downward relative to a surface of the inclined plate to form a concave portion, wherein a portion of the lower end portion of the paper guide that corresponds to the concave portion formed in the inclined plate is formed as a protrusion that protrudes downward relative to a lower end edge of the paper guide, and wherein the protrusion enters the concave portion.
The printer according to claim 5, wherein the inclined plate of the paper tray includes a region near both side portions in the width direction W that is formed as a recessed surface that continuously deepens forward and downward relative to a surface of the inclined plate toward both side edges, and wherein a rear end portion of the paper guide includes a region near the both side portions in the width direction W that is formed as a recessed surface, similar to the recessed surface of the inclined plate, that continuously deepens forward and downward toward the both side edge.

Description

[TECHNICAL FIELD] The present invention relates to a printer. [Background Art] A printer includes a drawer paper tray relative to a main body. The paper tray houses stacked multiple sheets cut to a predetermined size (hereinafter referred to as "paper"). The main body of the printer includes a pickup roller and a feed roller. These rollers rotate in contact with the uppermost paper among the multiple sheets housed in the paper tray, thereby feeding that paper into a paper feed path. When feeding paper using the pickup roller and the feed roller, the second paper stacked directly below the uppermost sheet (sheet positioned directly below uppermost sheet) may sometimes be fed together with the uppermost sheet in a stacked state due to static electricity or other factors, causing multiple feed. If multiple feed occurs, it may cause paper jam in a subsequent paper path or result in misalignment of the print in a print portion. Therefore, to eliminate the multiple feed, a retard roller is positioned to contact the feed roller in opposition, and the paper is fed by being sandwiched between the feed roller and the retard roller. In this case, the uppermost sheet contacting the feed roller receives the torque from the feed roller, causing the uppermost sheet to be fed. Since the retard roller receives the torque in the direction opposite to the feed direction of the feed roller, the second paper that advanced overlapping the uppermost sheet is stopped by the torque of the retard roller, separated from the uppermost sheet, and the multiple feed is solved (see, e.g., Patent Literature 1). [Prior Art Documents] [Patent Literature] [Patent Literature 1] Japanese Patent Publication No. 6035312B [Summary of Invention] [Problem to be solved] Here, it is necessary to set the contact pressure between the feed roller and the retard roller within a predetermined fixed range. However, in a printer where the feed roller is provided in the main body of the printer and the retard roller is provided in the paper tray, the contact pressure between the feed roller and the retard roller varies depending on the insertion depth of the paper tray relative to the main body. Therefore, it is desirable that the insertion depth of the paper tray relative to the main body be constant. However, the printer operates normally even if the insertion depth of the paper tray relative to the main body varies slightly due to manufacturing tolerances or handling of a printer. That is, even if the insertion depth relative to the main body is small, the printer operates normally as long as that small depth remains within a certain range, similar to the specified insertion depth. Therefore, the retard roller is configured so that the contact pressure does not vary significantly even if the position where it contacts the feed roller changes, causing the angle of oscillation to vary. Furthermore, it is required that the orientation of the common tangent line at the contact position between the feed roller and the retard roller does not significantly change due to the oscillation of the retard roller within the allowable range of the insertion depth of the paper tray relative to the main body (range within which printer operates normally). The present invention has been made in light of the above circumstances and aims to provide a printer where the direction of the common tangent line between the feed roller and the retard roller does not significantly vary due to the oscillation of the retard roller within the allowable range of the insertion depth of the paper tray relative to the main body. [Solution to Problem] The present disclosure provides a printer including a feed roller fixed to a main body of the printer, a paper tray that is detachably attached to the main body of the printer and houses many sheets, and a retard roller that contacts the feed roller and carries the paper housed in the paper tray by sandwiching the paper with the feed roller when the paper tray is attached to the main body of the printer, wherein the retard roller includes a base member fixed to a lower portion of a front portion of the paper tray, a roller member that contacts the feed roller, and a swinging arm member that rotatably supports the roller member at an upper end portion, has a lower end portion provided to be rotatable forward and backward relative to the base member, is disposed to extend in a height direction, and swings forward when the roller member contacts the feed roller. [Effects of Invention] The printer of the present disclosure prevents significant variation in the orientation of the common tangent line between the feed roller and the retard roller by the swing of the retard roller within the allowable range of the insertion depth of the paper tray relative to the main body. [Brief Description of Drawings] [FIG. 1] FIG. 1 is a cross section view with a vertical plane passing through a center of a width direction W of a dye-sublimation thermal printer (he