JPH10109783A - Paper feed device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure residual amount of sheet mounted on a paper feed tray table and if the residual amount comes less than determined value, give a user a sheet feed near end alarm. SOLUTION: This device has a vertically movable tray table for mounting sheet and pressure welding a top face of the sheet to a paper feed roller at a constant pressure and a means 16 for measuring thickness of the sheet and a means 17 for counting number of the fed sheet and a data storing means 12 for storing information of thickness of the sheet and paper feed number and a processing unit 10. Residual number of the sheet is found by measuring thickness of the sheet with different thickness at a plurality of time and calculating thickness of a sheet from used number that the paper feed number count means 17 has counted and if the residual number of the sheet is less than a predetermined value, sheet feed near end is displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder used for an image forming apparatus such as a copying machine, a printer, or a facsimile, and more particularly, to a paper feeder for a paper placed on a paper feed tray table of the paper feeder. The present invention relates to a sheet feeding device capable of issuing a warning of near-end of a sheet to a user when the remaining number of sheets becomes equal to or less than a certain value.

[0002]

2. Description of the Related Art An image forming apparatus is provided with one or more paper feed trays. The paper feed tray is filled with sheets, and sheets are supplied one by one from the trays to perform copying or copying. Printing and the like are performed. When there are a plurality of paper trays, sheets of different sizes are loaded in each paper tray, and the image forming apparatus automatically selects the paper, or the operator manually selects the paper from the operation panel. ,
Paper of a desired size is supplied.

[0003] Such a paper feed tray is basically inside the image forming apparatus and cannot be seen from outside the apparatus. For this reason, it is normal to know how much paper is left in the paper feed tray, and to know that the paper has run out after the paper runs out and the image forming apparatus stops operating.

[0004] From the above, from the user side,
There has been a demand for a device that can know in advance that the paper has run out when the paper is low. Therefore, a method has been proposed in which the amount of paper in the paper feed tray is displayed stepwise on a screen on an operation panel using a bar graph or the like.

[0005]

However, in the above bar graph, it is possible to know only about three stages, that is, whether the paper is full, little, or not at all. You can't tell just by looking at the display.

When the remaining paper is low,
Some warn of near-end, but this means that if the thickness of the stacked paper falls below a certain thickness, it will mechanically emit the near-end, and if the thickness of the paper put in the tray is different, The timing of issuing the paper near-end warning differs. In other words, a warning about the near end of the paper is issued when a large number of thin papers are still left, but a warning about the near end of the paper is finally issued when the number of thick papers is very small.

[0007] Also, the timing of issuing the near end is also different from the user, and there is a case where it is requested that the warning of the paper near end is issued earlier. In this case, it is difficult to adjust the timing of issuing the warning of the paper near end.

The present invention has been conceived in view of the above facts, and measures the number of remaining sheets placed on a sheet feed tray table of a sheet feeding device. It is an object of the present invention to provide a paper feeder that can issue a near-end warning to a user.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a tray table which can be moved up and down to load paper and press the upper surface of the paper against a paper feed roller at a constant pressure. A paper thickness measuring means for measuring the thickness of the paper, a paper feeding number counting means for counting the number of papers fed from the tray table, and information on the paper thickness and the number of paper fed. A data storage unit for storing, and an arithmetic processing unit, wherein the stacked sheet thickness measuring unit measures the thickness of the stacked sheets a plurality of times at different thicknesses, and the sheet number counting unit counts the number of times. The remaining number of sheets is obtained by calculating the thickness of one sheet from the number of used sheets, and when the remaining number of sheets becomes equal to or less than a preset value, a sheet near end is displayed.

[0010] Further, a configuration having a plurality of paper feed trays, wherein the preset value can be independently set for each paper feed tray, and a means for measuring the thickness of the paper using a variable resistor. Can be adopted.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a sheet feeding device of the present invention, and is a diagram showing a cross section of a sheet feeding tray. In the figure,
Reference numeral 1 denotes a paper feed tray, which has a U-shaped cross section. A tray table 2 is mounted in the paper feed tray 1 so as to be movable in the vertical direction in the figure, and sheets 3 are placed thereon.
The tray table 2 is maintained by a tray table vertical movement means (not shown) such that the upper surface 3a of the paper 3 always contacts the lower surface of the paper feed roller 4 at a desired contact pressure. A resistance element 5 is vertically mounted on the side of the paper feed tray 1, and a slider 6 provided on the tray table 2 comes into contact with the resistance element 5 to form a slide-type variable resistor 7. That is, the height of the tray table, that is, the thickness of the sheet, can be known from the resistance of the variable resistor 7.

FIG. 2 is a block diagram of the sheet feeding device of the present invention. A CPU of a computer is used as the arithmetic unit 10. The CPU also controls the entire image forming apparatus, and includes a ROM 11 and a RAM as data storage unit 12, and a display unit provided on an operation panel. 13, an operation panel input device 14, and the like.

In the present invention, the operation panel input device 14
Indicates that the number of near-end sheets can be set. When there are a plurality of sheet trays, it is desirable that the near-end sheet number can be set for each sheet tray.

Further, in the present invention, a tray table vertical moving means 15, a stacked paper thickness measuring means 16, and a paper feed number counting means 17 are provided. As described above, the tray table vertical moving means 15 raises and lowers the tray table so that the upper surface 3a of the paper 3 always contacts the paper feed roller 4 with a predetermined contact pressure. The loaded paper thickness measuring means 16 converts the resistance value measured by the variable resistor 7 into the thickness of the loaded paper. That is, the resistance value of the variable resistor 7 is
The resistance value changes according to the position of the slider 6 in contact with the resistance element 5, and the position (height) of the slider 6 changes according to the thickness of the paper 3. There is a proportional relationship between the two as shown in FIG. Note that the resistance value is shown as a percentage with the resistance value of the entire length of the resistance element 5 as 100%. Further, the data storage unit 12 stores information on the thickness of the sheet and the number of sheets fed.

FIG. 4 is a flowchart illustrating the operation of the present invention. Thus, the operation of the present invention will be described. When the image forming apparatus is started, it is determined whether a sheet is set (step 101). Then, the resistance value Rs of the variable resistor 7 is measured, and the thickness Ts of the entire sheet is obtained from the diagram of FIG. 3 (step 103). Next, from the stored thickness Ti per sheet, the number S of sheets to be stacked is obtained from the following equation. However, decimals are rounded off. S = Ts / Ti

Each time one sheet of paper 3 is consumed, 1 is subtracted from S and displayed on the display device 13 (step 10).
7). When the number of sheets consumed in the sheet feed tray reaches N (step 109), the thickness Tn of the entire sheet is measured again, compared with the previous thickness Ts, and the thickness per sheet is calculated by the following equation. Update Ti. Ti = (Ts−Tn) / N

Then, in the same manner as in step 103, the number S of stacked sheets is obtained and displayed. At the same time, the number of consumed trays is cleared (step 111). When it is detected that there is no paper (step 113), the remaining number of sheets is reset to zero and displayed, and the thickness at that time is corrected to zero (step 115). The near-end warning number for each tray is input in advance using an operation panel or the like, and when the number S of stacked trays becomes equal to or less than the near-end warning number,
A warning is displayed on the display device 13.

[0018]

According to the present invention as described above,
A tray table that can be moved up and down to load paper and press the upper surface of the paper against the paper feed roller with a constant pressure, a unit for measuring the thickness of the paper, Means for counting the number of sheets, data storage means for storing information on the thickness of the sheet and the number of sheets fed,
Calculating means for measuring the thickness of the stacked sheets, obtaining the number of remaining sheets based on the thickness, and displaying the near end of the sheet when the remaining number of sheets becomes equal to or less than a preset value. Therefore, the condition for the near end of the paper can be designated by the number of remaining papers. Thus, a near-end warning can be issued at a constant timing regardless of the thickness of the paper. For example, 5
If the number of sheets is set to zero, the user can know that the number of sheets has decreased to 50 or less when the near-end warning is displayed on both thick and thin paper, so that the user can be notified of the timing of paper supply more accurately.

Further, when there are a plurality of paper feed trays, it is possible to change the setting of the number of paper near-end warnings for each paper feed tray. This size of paper can easily respond to a user's request that a near-end warning need not be issued to the bare end or that a near-end warning need not be issued at all.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a sheet feeding device of the present invention.

FIG. 2 is a block diagram of a sheet feeding device of the present invention.

FIG. 3 is a diagram illustrating a relationship between a resistance value of a variable resistor and a thickness of stacked paper.

FIG. 4 is a flowchart illustrating the operation of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tray 2 Tray table 3 Paper 4 Feeding roller 7 Variable resistor 10 Computing device 12 Data storage means 13 Display device 15 Tray table up / down moving means 16 Stacked paper thickness measuring means 17 Feeding sheet counting means

Claims (3)

[Claims] 1. A tray table which can move up and down to load paper and press the upper surface of the paper against a paper feed roller with a constant pressure, a loading paper thickness measuring means for measuring the thickness of the paper, A sheet number counting means for counting the number of sheets fed from the tray table, a data storage means for storing information on the thickness of the sheet and the number of sheets fed, and an arithmetic processing means, The loaded paper thickness measuring means measures the thickness of the loaded paper a plurality of times at different thicknesses, calculates the thickness of one sheet from the number of sheets used during the counting by the fed sheet counting means, and calculates the thickness of the paper. A sheet feeder for calculating a remaining number of sheets and displaying a sheet near-end when the number of remaining sheets becomes equal to or less than a preset value. 2. The paper feeder according to claim 1, wherein the paper feeder has a plurality of paper feed trays, and the preset value can be set independently for each paper feed tray. 3. The sheet feeding device according to claim 1, wherein the means for measuring the thickness of the sheet uses a variable resistor.