JPH10291689A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely and inexpensively detect inclination of a printed medium, and avoid printing out of the printed medium, by providing an arithmetic device which stores carrying distance between the printed medium, which is carried by a carrying mechanism, and a detector and calculates inclination of the printed medium. SOLUTION: An printed medium 3 is carried in the auxiliary scanning direction by a printed medium carrying mechanism. First, position (XA, YA) derived from carrying distance YA shown when a detector 1 detects the edge of the printed medium which is carried by Y1 in the auxiliary scanning direction at a main scanning position A is stored in a storage. Next, the printed medium is carried by -Y1 , and the detector is moved to a main-scanning directed position B. The printed medium is carried again until the detector detects the edge of the printed medium, its position (XB, YB) derived from its carrying distance YB is stored. Inclination of the printed medium in relation to the main-scanning direction is calculated using the arithmetic device based on these two positional information (XA, YA), (XB, YB).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a mechanism and a method for detecting a printing medium in a printing apparatus.

[0002]

2. Description of the Related Art In a conventional printing apparatus, two detectors for measuring the inclination of a printing medium are provided in parallel with the main scanning direction.

[0003]

It is difficult to accurately adjust the inclination when setting a printing medium in a printing apparatus.
If the print-receiving medium is inclined, the print-receiving medium deviates from the initially measured print width while printing continues, and as a result, printing is performed at a position off the print-receiving medium. Due to such a state, for example, a defect such as breakage of a pin in a dot impact printer and ink stain on a platen in an ink jet printer have occurred.

[0004] In printing a form or the like, a problem arises in that printing cannot be performed at a desired location due to the inclination of the medium to be printed (form), and as a result, the medium to be printed is wasted.

In the prior art, since two detectors were required, an accurate inclination could not be measured due to a mounting position error of the detector and a difference in detection sensitivity of the detector.

Accordingly, the present invention provides a means for preventing the printing from being performed at a position off the printing medium by accurately detecting the inclination of the printing medium at low cost.

[0007]

A printing apparatus according to the present invention includes a print medium detector (hereinafter, referred to as a detector) for detecting the presence or absence of a print medium, a printing apparatus transport mechanism for transporting the detector, and a print medium transport mechanism. A print medium transport mechanism that transports the print medium, a storage device that stores the transport distance between the print medium and the detector that are transported by both transport mechanisms, and an arithmetic device that calculates the inclination of the print medium are provided. And

By detecting a plurality of edges of the printing medium by the above means, the inclination of the printing medium is detected.

[0009]

The edge of the print medium transported by the print medium transport mechanism is detected by a detector. This position is stored in the storage device as two-dimensional position information based on the distance (sub-scanning direction position) by which the medium to be printed has been conveyed by the conveying mechanism and the distance (main scanning direction position) by which the detector has been conveyed.

By detecting at least two edges, the inclination of the printing medium with respect to the main scanning direction is calculated by the arithmetic unit.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the drawings.

Reference numeral 1 denotes a detector for measuring the width of a medium to be printed, and reference numeral 2 denotes a printing apparatus transport mechanism to which the detector is attached. The detector moves in the main scanning direction.

Reference numeral 3 denotes a print medium, which is transported in the sub-scanning direction by a print medium transport mechanism.

First, the position (XA, YA) is stored in the storage device from the transport amount YA at which the detector detects the edge of the print medium transported Y1 in the sub-scanning direction at the position A in the main scanning direction. Next, the medium to be printed is conveyed by −Y1, and the detector is moved to the position B in the main scanning direction. The medium is conveyed again until the edge of the medium to be printed is detected by the detector, and the position (XB, YB) from the conveyance amount YB is stored in the storage device.

The position information (XA, YA) of these two points,
The inclination of the printing medium in the main scanning direction is calculated from (XB, YB) by the arithmetic unit.

[0016]

According to the present invention, the inclination of the medium to be printed can be correctly detected irrespective of the detector mounting position and the detector sensitivity, and printing outside the printable area can be prevented. Therefore, it is possible to prevent problems such as breakage of pins in a dot impact printer and contamination of ink on a platen in an ink jet printer, which have occurred in conventional printers and the like.

Further, a warning can be issued for an extreme inclination of the insertion of the printing medium, thereby preventing a printing error.

Further, according to the embodiment, since the detector provided in the conventional printing apparatus can be used, the present invention can be implemented at lower cost.

Further, by correcting the print image based on the inclination of the medium to be printed, higher quality printing can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a detection method diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 ‥‥ Printed medium detector (detector) 2 ‥‥ Printer transport mechanism 3 ‥‥ Printed medium

Claims (2)

[Claims] 1. A print medium detector for detecting the presence or absence of a print medium, a printing apparatus transport mechanism for transporting the same, a print medium transport mechanism for transporting the print medium, and a transport mechanism by these transport mechanisms. A storage device that stores the transport distance between the print-receiving medium and the detector, and an arithmetic device printing device that calculates the tilt of the print-receiving medium, wherein the tilt of the print-receiving medium with respect to the printing direction is determined by the detector. A printing device characterized by detecting. 2. The printing apparatus according to claim 1, wherein the detector also serves to detect the width of the print target medium.