JP2001116674A - Method and apparatus for measuring curl - Google Patents

Abstract

(57) Abstract: A method and an apparatus for measuring the curl of paper and paperboard, particularly paper used in an electrophotographic copier or printer. A method and an apparatus for measuring curl including a step of holding a sheet; a step of heating the sheet in a non-contact manner; and a step of measuring a force of the sheet to deform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring curl of paper and paperboard.
In particular, the present invention relates to a method and an apparatus for measuring curl due to rapid heating such as thermal fixing in an electrophotographic system.

[0002]

2. Description of the Related Art The term "sheet" used herein refers to paper, paperboard, PE
T, RC paper (photographic support), wood, plastic, cloth,
A sheet of a sheet such as a leather is generally referred to. Curling is a phenomenon in which these sheets bend due to environmental changes, external force or heating. Here, paper will be described as an example.

[0003] It is well known that paper curls due to environmental humidity changes. The curl was evaluated in a certain environment, for example, at a temperature of 20 ° C./relative humidity of 65%, and slightly dried,
Performed after 5 minutes at 05 ° C. As a method for evaluating the curl, a method of measuring the amount of swelling from the plane of the four corners of the curled paper and a method of calculating the curl curvature as a curvature are generally performed. These measure the shape of the resulting curled paper.

[0004] Curling also occurs when an external force is applied. For example, if a piece of paper is placed on the corner of a desk, the curled surface will curl inward. This indicates that the paper is curled by a mechanism inside the machine. Also,
In some cases, the paper is wound into a cylindrical shape. At this time, the paper may be curled in a rolled shape called a curl.

Further, in a copying machine or a printer of an electrophotographic system, there is a step of heating with a high-temperature heat fixing roll in order to fix toner adhered as an image on paper. Such rapid heating from one side is also considered to be a factor of paper curl.

In particular, paper curl in a copying machine or a printer causes not only a bad appearance but also a cause of jamming of the paper inside the copying machine and a cause of failure in stacking of copied paper. For this reason, papers with less curl are required, and research and development are being promoted.

In order to develop a sheet with less curl,
It is important to evaluate the curl factor of the sheet.

A method of actually passing paper through a copying machine and measuring the curl has been used. This is important as a realistic overall evaluation. However, in order to evaluate what kind of characteristics of paper are factors, it is necessary to measure each factor.

[0009] Since curl is caused by several different factors as described above, a separate evaluation is required for each of these factors. Thus, methods and devices for measuring physical properties related to curl have been developed.

[0010]

However, little is known about the curl during one-sided heating of a sheet, and there is no measuring method or apparatus. Recently, with the increase in speed and quality of electrophotographic copiers and printers, improvement of the curl of the paper used in such machines has become an important issue. In the paper used in such an electrophotographic system, it is necessary to evaluate the influence of the above-mentioned thermal fixing, that is, the curl when the sheet is heated on one side. In the past, most of the evaluation of curl was to measure the shape after curling, but it was evaluated by separating the curling force and the hard-curling force such as rigidity, that is, the hard-to-bend force. I couldn't.

It is an object of the present invention to provide a method and apparatus for measuring the force of a sheet to curl during heating.

[0012]

SUMMARY OF THE INVENTION The present invention provides a method for measuring curl, comprising the steps of holding a sheet, heating the sheet in a non-contact manner, and measuring a force to deform the sheet. It is.

Further, the present invention is an apparatus for measuring curl, comprising: means for holding a sheet; means for heating the sheet in a non-contact manner; and means for measuring a force to deform the sheet.

[0014]

Embodiments of the present invention will be described with reference to the drawings. The method and apparatus for measuring curl according to the present invention are configured, for example, as shown in FIG. FIG. 1 is a configuration diagram of the curl measuring device. As shown in FIG. 1, the curl measuring device includes a sheet 2 to be measured and a fixed clamp 3 for holding the sheet 2.
1, a measuring clamp 32, a non-contact heating device 4 for heating the sheet surface, and a force measuring device 5 attached to the measuring clamp 32.

The sheet 2 is a sample sheet to be measured, and is set on a fixed clamp 31 as shown in FIG. The sample sheet needs to be large enough to hold the left and right clamps in the width direction and between the heated clamps, and has a sheet shape with a height.

The fixed clamp 31 and the measuring clamp 32
The seat 2 is held from left and right. The fixed clamp 31 holds the sheet 2 so as to sandwich it. The fixed clamp 31 and the measurement clamp 32 sandwich the sheet 2, but at this time, the sheet 2 is not fixed so as not to move. Even after the sheet 2 is held by the fixed clamp 31 and the measurement clamp 32, the sheet 2 is held so as to be easily moved.

The measuring clamp 32 measures the force of the sheet 2 curling by heating. For example, as shown in FIG. 1, the measuring clamp 32 has a rotating mechanism 33, and the force to be rotated is measured by the force measuring device 5.

Also, for example, the measuring clamp 32 is shown in FIG.
As shown in (1), it is also possible to directly connect to the force measuring device 5 for measurement.

As the force measuring device 5, a torque sensor or a load cell is used. The measured force is displayed externally. The measured force can also be converted. Further, the measured force is output as a signal, taken into a storage device or a computer, and can be stored, analyzed, displayed in a graph, and the like.

Non-contact heating device 4 for heating the sheet surface
Various heating devices can be used. Those using electric heaters with nichrome wires, infrared lamps, gas appliances, etc. General incandescent lamps can also be used as long as they have the appropriate amount of heat for heating. A hot plate that can control the surface temperature can also be used.

The measurement is performed in the following procedure. The sheet 2 is set on the fixed clamp 31 and the measurement clamp 32, and the measurement by the force measuring device 5 is started. The heating is started by the non-contact heating device 4. Although the sheet is curled by heating, the shape cannot be largely changed because the sheet is held by the fixed clamp 31 and the measurement clamp 32. The curling force at this time is measured by the force measuring device 5.

If necessary, the heating is stopped, and the subsequent change in the curling force can be continuously measured by the force measuring device 5.

[0023]

Embodiments of the present invention are described below.

Example 1 An apparatus shown in FIG. 1 was manufactured. Each of the fixed clamp 31 and the measuring clamp 32 is formed of a two-piece plate-shaped metal plate.
A mechanism was used to fasten the metal plates with screws. Fixed clamp 3
1 was fixed to the curl measuring device 1. As shown in FIG. 1, the measuring clamp 32 has a rotating mechanism 33 so that the force to be rotated can be measured by the force measuring device 5.

An illumination lamp (Toshiba Reflex Lamp 200W) was installed as the heating device 4 so that the sheet 2 could be uniformly heated without contact. A guard plate was installed in front of the lighting lamp so that only the sheet surface was not heated, so that only the sheet surface was heated. Heating can be turned on and off with a switch, but since the lighting lamp has residual heat, the lighting lamp and the guard plate are separated from the sheet after heating is stopped.

The state of heating was confirmed by using a radiation thermometer.

The measurement was performed according to the following procedure. The sheet 2 is set on the clamp 3 and the measurement by the force measuring device 5 is started. The heating was started by the non-contact heating device 4. The sheet curls due to heating, but the fixed clamp 31 and the measuring clamp 32
The shape cannot be changed greatly because it is held at The curling force at this time was measured by the force measuring device 5.
The signal of the force measuring device 5 was taken into the computer via the A / D converter every second.

FIG. 3 shows an example of measuring the curl of the paper every second when the PPC paper used in the copying machine is clamped, heated for 30 seconds after elapse of 30 seconds, and then stopped.

Example 2 An apparatus shown in FIG. 2 was manufactured. In FIG. 2, the measuring clamp 3
2 is attached to the tip of the force measuring device 5. Embodiment 1 shown in FIG. 1 except for the difference between the measuring clamp 32 and the force measuring device 5
It has the same configuration as.

Although the present invention has been described based on the embodiments, the present invention is not limited to the embodiments and can be variously modified.

[0031]

According to the present invention, it is possible to measure the curl behavior of a sheet when one side of the sheet is heated, which is a problem in an electrophotographic copier or printer, and is useful in the development of a sheet with less curl. Information can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a curl measuring device.

FIG. 2 is a configuration diagram of a curl measuring device according to a second embodiment.

FIG. 3 is an example of a curl measurement result.

[Explanation of symbols]

 2 Sheet 4 Heating device 5 Force measuring device 31 Fixed clamp 32 Measurement clamp 33 Rotation mechanism

Claims (2)

[Claims] 1. A method for measuring curl, comprising: holding a sheet; heating the sheet in a non-contact manner; and measuring a force of the sheet to deform. 2. An apparatus for measuring curl, comprising: means for holding a sheet; means for heating the sheet in a non-contact manner; means for measuring a force of the sheet to deform.