JPS612589A - Page end detector for typewriter - Google Patents

Abstract

PURPOSE:To enable a page and condition to be accurately detected independently of the paper size, the line space and manual operations of a platen, by a method wherein a trailing end part of a printing paper wound around a platen is detected from a change in reflected light received by a light-receiving part. CONSTITUTION:The paper 14 clamped between the platen 11 and a paper holder 12 is rotated in the direction of an arrow D together with the platen 11. In the page end condition, the lower end of the paper 14 comes to the position of a hole 15 provided in the holder 12. The path of a ray emitted from a light-emitting element 22 set on the inside of a module 20 is indicated by a broken line E. The ray reaches a light-receiving element 21, and is converted into a photoelectric current, which is transmitted through a wiring 23. Therefore, the quantity of light reflected and reaching the element 21 is smaller when the light is reflected by the platen 11, since the platen 11 is covered by a black carbon rubber, and the quantity is larger when the light is reflected by the paper 14, since the paper 14 is white in color. Accordingly, by detecting the difference in the quantity of light received, it is possible to discriminate the condition in which the paper is inserted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a page end detection device for a typewriter that detects the end of printing paper or the end of printing paper.

[Technical background of the invention]

There are two known methods for detecting paper out or page end when using a typewriter or the like.

The first is a mechanical method using an end-of-page indicator, and the second is an electronic method using an IC counter. These conventional methods will be explained below.

First, a mechanical method using a page end indicator will be explained with reference to FIG. FIG. 1 shows a platen 1, which is a part of a typewriter, and is composed of an iron cylinder 3 covered with a rubber part 2 made of a material such as carbon rubber.

The rubber portion 2 has the purpose of absorbing the impact caused by the markings of a typewriter and facilitating printing. The platen is also provided with a platen knob 4 and a page end indicator 5 that moves in conjunction with the platen knob 4 but can also be rotated independently. Numbers are displayed on the outer periphery of the page end indicator 5. This number usually indicates the length of the printable paper margins in inches. How to use the page end indicator 56 will be explained below.

First, align the top edge of the paper to be used parallel to the top of the platen 1, then rotate the page end indicator 5 independently of the platen knob 4 until the page end indicator 5 reaches a predetermined number depending on the size of the paper. Set it so that it is displayed at the top of indicator 5. When the typewriter is operated, the platen 1, platen knob 4, and page end indicator 5 rotate together with the paper by pressing the line feed key. As you continue to use the typewriter, as you approach the page end and the length of the paper margin becomes less than the outer circumference of platen 1, the number at the top of the outer circumference of the page end indicator will indicate the paper margin length. . This is because the number of the page end indicator 5 has been set in advance to match the size of the paper.

Therefore, it is possible to detect the page end state while continuing to operate the typewriter. However, this method had the following problems.

First, the page end indicator 5 simply displays numbers, so the page end indicator 5 always
If you are not careful, there is a high possibility that you will overlook the page end condition.

Second, the number set for the page end indicator 5 differs depending on the paper size, such as A4.84, so the number set must be changed every time the paper size is changed.

Third, the number on the page end indicator 5 indicates the absolute paper margin length, so even if the number is the same, if the line spacing is different, the number of remaining lines that can be pressed will also be different.
It is not possible to directly know the number of remaining lines, which is the most important thing to know.

Next, regarding the second method using an IC counter,
This will be explained using figures. In Figure 2, typewriter key 7
The numerical value inputted from is inputted to the IC counter 8. This IC counter 8 has the function of setting the input numerical value internally and driving a digit display device 9 such as an LED and an alarm device 10 that notifies the page end status.

A mechanism for detecting a page end state by the IC counter 8 will be explained. First, after setting a sheet of paper in the typewriter, the IC counter 8 is put into line number setting mode, and the number of lines to be pressed is input using the key 7. The number set at this time is displayed on the display device 9. After setting, when a typewriter is used, the IC counter 8 counts down by pressing the line feed key. Eventually, as the end of the page approaches, an alarm will be activated when 1 to 3 lines before the set number of lines are detected. 110 is activated to signal an end-of-page condition.

This electronic method using the IC counter 8 also has the following problems.

First, since the IC counter 8 is independent of the movement of the platen 1, if the paper is rewound for corrections, additions, etc., the counts will no longer match. .

Second, like the first method, it is necessary to reset the settings each time the paper size or line space changes.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and it is an object of the present invention to provide a typewriter page end detection device that accurately detects the page end state regardless of paper size, line space, and manual operation of the platen. purpose.

[Summary of the invention]

To achieve this purpose, the typewriter page end detection device according to the present invention is a typewriter that prints characters, etc. on the printing paper while sequentially feeding the printing paper wound around the platen by rotating the platen. A page end detection device for a writer includes: a light emitting unit that illuminates a predetermined position on the platen; a light receiving unit that receives reflected light from the predetermined position that is emitted by the light emitting unit; The present invention is characterized in that it includes a detection section that detects the trailing edge of the printing paper wound around the platen based on a change in reflected light.

[Embodiments of the invention]

A page end detection device for a typewriter according to an embodiment of the present invention is shown in FIG.

FIG. 3 shows the platen 11 of the typewriter in the page end state from the back side.

The platen 11 is coated with black carbon rubber, etc.
A paper holder 12, usually made of metal, is provided. This paper holder 12 is provided with rollers 13 for smooth movement of the paper. The paper holder 12 serves to fix the paper 14 to the platen 11. The paper holder 12 is also provided with slit-like holes 15 and 16 at two locations for detecting the end of a page.

FIG. 4 is a sectional view of the typewriter platen 11, paper holder 12, and page end detection device according to the present invention. A sheet of paper 14 in a page-end state is sandwiched between the paper holder 12 and the platen 11. A module 20 according to this embodiment is provided outside the paper holder 12, and this module 20 includes a light receiving element 21 such as a PIN diode, a CCD, and a color identification diode, and a light emitting element 22 such as an LED or a laser diode.
It is an integration of the. This module 20 is movable along the paper holder 12 guided by metal rails 24 and has flexible electrical wiring 23.

FIG. 5 is a cross-sectional view at a different position from FIG. 4, and shows the paper release mechanism that moves the paper holder 12. In this figure, the double circle indicates the movable fulcrum,
White circles and black circles indicate fixed fulcrums. The paper release lever 27 is tensioned by a spring 28 and the metal plate 29 is tensioned by a spring 30. The metal rod 31 has a long arm 32 that reaches the underside of the paper holder 12. The microswitch 33 is for interlocking the paper release mechanism and the page end detection device. That is, when the metal plate 29 rotates, the movable part 34 of the micro switch 33 is pushed, and the electrical connection between the metal electrodes 35 changes.
This activates the page end detection device.

Next, the page end detection device according to this embodiment will be explained in more detail with reference to FIGS. 3, 4, and 5.

FIG. 3 shows a case where the paper 14 is sandwiched between the platen 11 and the roller 13 and moves together with the platen 11 in the direction of arrow C, reaching the page end state. Since the edge of the paper 14 is about to come off the roller 13, the paper is shifted and the paper surfaces A and B exposed to the holes 15 and 16 are unbalanced. The left hole 15 according to this embodiment is a paper guide (usually placed at the left end of the platen 11).
(not shown), and the holes 16 on the right side are provided at spaces narrower than the smallest size of paper that can be typed on. This interval is shown as D in Figure 3. It was shown in on the other hand,
FIG. 4 shows a cross section in a page end state. Paper 1 sandwiched between platen 11 and paper holder 12
4 rotates together with the platen 11 in the direction of the arrow. In the page end state, the bottom edge of the paper 14 is placed in the paper holder 12.
It approaches the upper hole 15. At this time, the module 20 is located below the hole 15 and is detecting the paper 14 and the platen 11. The trajectory of the light beam emitted from the light emitting element 22 set inside the module 20 is indicated by a broken line E. The trajectory of this light beam reaches the light receiving element 21 and becomes a photocurrent that is transmitted through the electrical wiring 23. The trajectory E of this light beam hits the outer periphery of the platen 11 or the paper 14. Therefore, the amount of light that is reflected and returns to the light receiving element 21 is:
Because the outer periphery of the platen 11 is covered with black carbon rubber, if it hits the paper 14, the paper 1
4 is white, so it is relatively common.

In other words, by detecting this difference, it can be determined that the paper is inserted.

Now suppose you are using a typewriter and are nearing the end-of-page condition. At this time, the time comes when the paper 14 passes through the holes 15 and 16 provided on the paper holder 12. As described above, the amount of reflected light decreases and it is determined that the page is in the end state. Therefore, in this method, when the margin length of the paper 14 reaches a certain length, it is determined that the page end state has occurred. therefore,
This method has the advantage that the margin length of the paper can be known regardless of the paper size or line space.

Furthermore, in FIG. 3, let us consider a case where the edge of the paper 14 in the page-end state has come off the roller 13 and is bent over. In this case, the areas Δ and B of the paper surface exposed to holes 15 and 16
An imbalance occurs.

If you continue typing in this state, the lines will be tilted, so you need to prevent this. If the light-receiving area of the light-receiving element 21 shown in FIG. 4 is made large, it is possible to detect this imbalance using the method described above and stop typing.

Furthermore, in this embodiment, the paper release lever and the page end detection device are linked. This will be explained using FIG. 5. When the paper release lever 27 is moved to the left in the direction E in FIG. 5, the metal plate 29 moves downward in the direction F and the metal rod 31 moves upward in the direction G. That is, the paper holder 12 is lifted upward and moves to fix the paper between it and the platen 11. Conversely, when the paper release lever 27 is moved to the left in direction E, the paper holder 12 moves downward and enters the released state.

Now, when the paper release lever 27 is moved to the left, the metal plate 27 is pushed downward in the direction F, pushing the protrusion 34 of the microswitch 33 and changing the electrical connection state of the metal electrode 35. Therefore, the paper release lever 27 can be used in conjunction with the page end detection device according to this embodiment. Normally, when the paper is released, there is no need to detect the page end state, so when the detection device is left unused, the above method can prevent unnecessary alarms. The page end detection device according to this embodiment detects a state in which the margin length of the paper is constant regardless of the paper size or line/space. Considering the case where the margin length is also adjusted, in this embodiment, the module 20 shown in FIG. 4 is made movable, and the settings can be changed using the metal rail 24 as a guide.

Next, the control of the page end detection device according to this embodiment is performed in the sixth step.
This will be explained using the block diagram shown in the figure. The output signals of the light receiving section 211 for the hole 15 and the light receiving section 212 for the hole 16 are input to the fluctuation detecting section 37 and the comparing section 38, respectively. The fluctuation detection unit 37 detects whether or not the magnitude of the signals from the light receiving unit 211 and the light receiving unit 212 changes. When the end of the paper 14 passes through the hole 15. Output to 36. The comparing unit 38 compares the magnitude of the signals from the light receiving unit 211 and the light receiving unit 212, and if the magnitudes of the signals differ by more than a predetermined value, it is determined that the paper 14 is tilted and outputs a paper shift signal to the control unit. . When the control section 36 receives the page end signal from the fluctuation detection section 37, it outputs the remaining number of lines to the display section 43. This remaining number of lines is sequentially subtracted by a line feed signal, and the current number of remaining lines is displayed. When the page end signal is input, an alarm signal is also output to the alarm device 44, and an alarm sound is emitted to notify the operator that the page end is near. Further, when a paper shift signal is input, another alarm signal is output to the alarm device 44, and a different alarm sound is emitted to notify the operator of the paper shift. Note that the signal from the microswitch 33 is input to the control unit 36, and the above-mentioned control operation is performed only when the paper holder 12 is lifted by the paper release lever 27 and the paper 14 can be printed. Although the present invention was applied to a typewriter in the previous embodiment, it goes without saying that it can also be applied to a printing device such as a printer. Further, the present invention is not limited to the above embodiments, and various modifications are possible.

〔Effect of the invention〕

As described above, according to the present invention, the end of the paper can be reliably detected regardless of the paper size or printing method. Since the operator normally only looks at the document, by providing an audible alarm device, it is possible to more reliably notify the operator of the page end.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of a conventional page end detection method. FIGS. 3, 4, and 5 are structural diagrams of a typewriter page end detection device according to an embodiment of the present invention. FIG. 6 is a block diagram of the same page end detection device. 1...Platen, 2...Rubber part, 3...Iron tube, 4
... Platen knob, 5... Page end indicator, 7... Typewriter keys, 8... Counter, 9... Digit display device, 10... Alarm device,
11... Platan, 12... Paper holder, 13
... Roller, 14 ... Paper, 15.16 ... Hole, 17 ... Arm, 18 ... Type, 19 ... Ink ribbon, 20 ... Module, 21 ... Light receiving element , 22... Electric wiring, 27... Paper release lever 1, 28... Spring, 29... Gold plate, 30...
...Spring, 31...Metal rod, 32...Arm, 33
...Micro switch, 34...Movable part, 35...
- Electrode, 36... Control unit, 37... Fluctuation detection unit, 3
8... Comparison section, 43... Display section, 44... Alarm device, 211... Light receiving section corresponding to hole 15, 212...
- Light receiving part corresponding to hole 16. Tea 3 Figure C Vines 5 Day Figure 6

Claims (1)

[Claims] 1. A page end detection device for a typewriter that prints characters, etc. on printing paper wound on the platen while sequentially feeding the printing paper wound around the platen by rotating the platen, comprising: a light emitting section that illuminates a predetermined position; a light receiving section that receives reflected light from the predetermined position that is irradiated by the light emitting section; A page end detection device for a typewriter, comprising: a detection unit for detecting the end of printed printing paper;