Sheet feed mechanism of printer, and printer

Abstract

A sheet feed mechanism of a printer includes a sheet feed roller arranged so as to be rotatable about an axis in a direction orthogonal to a sheet conveying direction in plan view such that its apex is made to face a sheet conveying path on the downstream side in the sheet conveying direction, a sheet pressure-contact member arranged to be capable of pressing a sheet against the sheet feed roller, and a sheet trailing end guide portion having a guide surface which gradually guides a trailing end of the sheet released from abutment on the sheet feed roller toward the downstream in the sheet conveying direction.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application contains subject matter related to and claims the benefit of Japanese Patent Application JP2007-296699 filed in the Japanese Patent Office on Nov. 15, 2007, the entire contents of which is incorporated herein by reference.BACKGROUND OF THE DISCLOSURE[0002]1. Technical Field[0003]The present invention relates to a sheet feed mechanism of a printer constructed such that a sheet may be conveyed by rotating a sheet feed roller while the sheet is sandwiched between the sheet feed roller and a sheet pressure-contact member, and a printer including the sheet feed mechanism.[0004]2. Related Art[0005]Thermal printers that make a plurality of heat-generating elements of a thermal head generate heat selectively on the basis of recording information, thereby performing recording on a recording medium, are widely utilized.[0006]A sectional view of major portions in a related-art printer which performs desired recording using a ...

AI Technical Summary

Benefits of technology

[0014]It is desirable to provide a sheet feed mechanism capable of preventing conveyance unevenness resulting from a change in load to a sheet at the time of roller slip-out, and a printer including the sheet feed mechanism, capable of obtaining excellent recording results.

[0016]According to exemplary sheet feed mechanisms, the sheet trailing end guide portion may gradually guide the trailing end of the sheet released from pressure contact with the sheet feed roller, along the guide surface toward the downstream in the sheet conveying direction. Thereby, an abrupt change in the load applied to a sheet can be suppressed and sheet conveyance unevenness can be reduced. Therefore, generation of poor recording results resulting from an abrupt load change at the time of roller slip-out of the trailing end of a sheet can be prevented. In that case, the sheet trailing end guide portion may act uniformly irrespective of the thickness of the sheet. In addition, in the embodiments of the invention having a construction in which the sheet is conveyed by the sheet feed roller, and by the sheet pressure-contact member which makes pressure contact with the sheet feed roller via the sheet, it may be possible to form desired recording, without providing a margin at the leading end of the sheet.

[0018]Also, the sheet trailing end guide portion may catch the trailing end of the sheet released from pressure contact with the sheet feed roller, in a position which is higher than the sheet guide surface and lower than the apex of the sheet feed roller, and gradually guide it along the guide surface toward the downstream in the sheet conveying direction. Thereby, an abrupt change in the load applied to a sheet can be suppressed and sheet conveyance unevenness can be reduced.

[0024]The sheet feed mechanism can reduce a change in the load to a sheet at the time of roller slip-out, thereby preventing conveyance unevenness of the sheet. Thus, excellent recording can be obtained.

[0025]As mentioned above, according to various exemplary embodiments, a change in the load to a sheet at the time of roller slip-out can be reduced, thereby preventing conveyance unevenness of the sheet, and excellent recording can be obtained. Moreover, by including such a sheet feed mechanism, it may be possible to exhibit an excellent effect that the printer is suitable as a printer which obtains recording results in which a margin is not formed at the leading end of the sheet in the sheet conveying direction.

Problems solved by technology

Under the influence of these, there is a problem in that white lines are formed in recording results in recording positions.

The load change which causes such a problem becomes large as sheet thickness becomes large.

Thus, the conveyance of a sheet becomes poor under the influence of the load change.

However, in the related art disclosed in Japanese Unexamined Patent Application Publication Nos. 2005-8343 and 2007-83500, the control for which even a difference in the load change which changes depending on the thickness of sheets to be used is taken into consideration is difficult, and the positive effect that conveyance is stabilized cannot be expected.

Therefore, this method cannot be adopted in a case where recording results in which a margin is not formed are desired.

Further, in connection with the sandwiching of a sheet by the conveying roller, a release mechanism which releases the pressing of the sheet pressure-contact member against the sheet feed roller becomes necessary, and the construction of the printer becomes complicated.

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