JPH0436606A - Sheet size detector - Google Patents

Abstract

PURPOSE:To detect a sheet size without depending upon a paper feed container by judging the sheet size from a detected quantity obtained by detecting a sheet with a reflection type photosensor during its movement. CONSTITUTION:A motor 8 moves the reflection type sensor 6 from the position facing the sheets of minimum size among sheets 2 which differ in size to the position corresponding to a transverse directional end perpendicular to the feeding direction of the sheets 2 as to all the sheets 2 differing in size. The detected quantity of the sheet 2 by the photosensor 6 during its movement is inputted to the CPU 101 of a printer main body to be a judging means. The CPU 101 judges the sheet size while corresponding to the detection time. This method eliminates the need to provide the paper feed container 1 itself with any mechanism and by such a simple device, the sheets 2 which differ in size in the transverse direction are detected. Consequently, the sheet size can be detected independently without depending upon the paper feed container.

Description

DETAILED DESCRIPTION OF THE INVENTION [1 Above] Next 1 The present invention provides a paper feed container of one size installed at a predetermined position of a paper feed container of an image forming apparatus that can use sheets of multiple sizes. The present invention relates to a sheet size detection device that detects the size of a sheet. Conventional technology Conventional printing paper size detection used in image forming devices such as copying machines and printers generally uses a shielding plate that provides a one-to-one correspondence between a photo ink printer and various paper sizes. FIG. 13 shows an example of conventional size detection. In this method, five transmission type photosensors 6' are attached to the main body 100 of the image forming apparatus, and size detection is performed by activating the photosensors depending on the pattern of a shielding plate attached to the paper feed cassette 1 side. ing. That is, as shown in FIG. 3C, a cutout 20a is provided in a part of the shielding plate 20, and among the five photosensors, only the sensor at the position corresponding to the cutout 20a is turned on, and the other sensors are turned on. The sensor is turned off so that one type of paper size can be detected with one shielding plate. FIG. 2C shows an example of the internal circuit of such a sensor. This type of sensor uses shielding plates of different shapes for each size of paper, so it is necessary to replace the shielding plate for each paper used. Another method is to use a shielding plate for each paper size, but a method using a button switch,
There is a method in which the operator inputs the size from the operation panel. However, with such conventional methods, it has been difficult to make the paper feed cassette universal. As a countermeasure for this, bush switches, reed switches, etc. are arranged side by side in the width direction and length direction of the paper, and when the side guides and end guides of the cassette are moved, these switches are activated to detect the size. The method is adopted. However, according to this method, for example, in the case of an image forming apparatus that can print up to A3 size, there are many different sizes that need to be detected, so there are problems such as a large number of switches, making control complicated and increasing costs. there were. Problem to be Solved The present invention solves the above problems in the prior art, and claims 1
An object of the invention is to provide a sheet size detection device that can independently detect a sheet size without depending on a paper feed container and has a reduced cost. It is an object of the present invention to provide a sheet size detection device capable of detecting a wider variety of sheet sizes in addition to the above-described invention.
In addition to the problems of the invention, it is an object of the present invention to provide a sheet size detection device that can detect a wider variety of sheet sizes with a simple mechanism. In order to solve the above-mentioned problems, the invention of claim 1 provides an image forming apparatus that is installed at a predetermined position in a paper feed container of an image forming apparatus that can use sheets of a plurality of sizes. A sort size detection device that detects the size of sheets of one type of size that has been placed, comprising: a reflective photosensor that detects whether there is a sheet at an opposing position; and a sheet of the smallest size among the plurality of size sheets. moving means for moving the reflective photosensor from a position facing the sheet to a position corresponding to a widthwise end of all of the sheets of the plurality of sizes, which is a direction perpendicular to the direction in which the sheets are fed; The invention according to claim 2 is characterized in that the sheet size is determined in accordance with the amount of detection detected by the type photosensor while the sheet is being moved. From a position facing the smallest sheet among the sheets of the plurality of sizes to a position corresponding to the longitudinal end of all of the sheets of the plurality of sizes, which is a direction parallel to the direction in which the sheets are fed. The invention of claim 3 is characterized in that the reflective photosensor is moved, in addition to the feature of the invention of claim 1, the moving means moves the reflective photosensor to an end in the width direction of the sheet. Instead of moving the reflective photosensor, the reflective photosensor may be moved in one arcuate trajectory opposite to the sheet through the edges of two mutually orthogonal sides of the sheet for all of the sheets of the plurality of sizes. Features. According to the invention of claim 1, the reflective photosensor is moved by the moving means from the position corresponding to the smallest size sheet to the widthwise end of the sheets of all types of sizes, and the reflective photosensor is moved while the reflective photosensor is moving. Since the determining means determines the sheet size according to the detected amount of the sheet, for example, the detection time, there is no need to provide any mechanism in the paper feed container itself, and sheets of different sizes in the width direction can be handled with a simple device. can be detected. According to the invention of claim 2, in addition to the above-mentioned effect, since the reflective photosensor is also moved in the sheet feeding direction by the moving means, the detection amount in the sheet feeding direction is also determined by the determining means. Therefore, the sheet size can be detected even if the sheets have the same length in the width direction. According to the third aspect of the invention, each type of sheet installed is detected by moving the reflective photosensor in one orbit in an arc shape passing through the ends of two mutually orthogonal sides of the sheet, so that each type of sheet is detected. Different trajectories can be detected for each sheet, and all types of sheet sizes can be detected with a simple mechanism. Figure 1 is a perspective view showing an embodiment of the sheet size detection device of the present invention, and Figure 2 is a side view thereof. In a vapor cassette 1 serving as a paper supply container, one type of recording paper 2 among sheets of a plurality of sizes used in an image forming apparatus is aligned by side plates 3a, 3b and an end plate 4, and is arranged in a predetermined manner. That is, in this embodiment, it is installed at the central reference position. The vapor cassette 1 with the recording paper 2 installed is shown in FIG.
) and FIG. 3, the cassette is guided by cassette guides 5a and 5b of a printer 100, which is an example of an image forming apparatus, and set at a predetermined position. When the paper cassette 1 is set in the printer 100, the reflective photosensor 6 that detects the presence or absence of sheets is inserted into the groove of the sensor arm 7, which forms part of the moving means, as shown in FIG. Recording paper 2 in the X direction in the figure.
It is movably installed facing the In this embodiment, the moving means includes a motor 8, a drive wire 9 driven by the motor 8, a pulley 10a around which the wire is wound, a job 10c, 10d, 10e, and a printer 1.
It is comprised of a guide rod 11 and a guide frame 12 that are attached to the main body of the sensor arm 7 and guide the sensor arm 7, and a stopper lever 15 that includes a plunger solenoid 13 and a friction member 14 that are attached to the sensor arm 7. With this configuration, as shown in FIGS. 4 and 5,
The reflective photosensor 6 can be moved in the X direction, which is the width direction of the recording paper 2, and in the Y direction, which is parallel to the feeding direction thereof. That is, in FIG. 4, when the plunger solenoid 13 is turned off and the friction member 14 is not in pressure contact with the pulley 10d as shown in FIG. 4(b), the friction member 14 is driven by the motor 8 as shown in FIG. 4(a). Even when the wire 9 is pulled, the pulley 10d rotates freely and its position does not move in the Y direction, while the reflective photosensor 6 is hyper-moved in the X direction due to the movement of the wire. In this case, the reflective photosensor 6 is moved from a position where it can at least face and detect the smallest sheet of paper to the widthwise end of the largest sheet of paper. - Plunger solenoid 13 as shown in Figure 5, etc.)
is turned on and the friction member 14 is pressed against the pulley lOd, the drive wire 9 is fixed integrally with the sensor arm 7, the pulley 10d does not rotate, and the reflective photosensor 6
is moved only in the Y direction, which is parallel to the feeding direction of the recording paper 2, as shown in FIG. This movement is performed at least to the trailing edge of the largest size paper. When the reflective photosensor 6 moves in this way and detects the sheet size, this signal is input to a determining means, for example, CPLIIOI of the printer main body. FIG. 6 is an explanatory diagram when the sheet size is detected by moving the reflective photosensor 6 in the X direction. Figure (a) shows the minimum size paper A6 in the paper cassette 1.
The figure shows a state in which recording paper from A3 to the largest size is installed in the vertical feeding direction (A6 R =, A4 R, A3 R) with the center reference, and the reflective photosensor 6 is shown from a position where it can also detect the smallest size paper. It is moved in the X direction as shown in FIG. FIG. 2B shows the dimensions from the center to the widthwise edge of each size of recording paper. The reflective photosensor 6 moves in the width direction from the center position of the figure, for example, and is turned on by the reflected light in a certain area of the paper, and comes off from each edge when recording paper of each size is set. and turns off. Therefore, since the amount of detection from when the sensor turns on to off differs depending on the size of each recording paper as shown in FIG. cpui shown in Figure 1. 1, it is recognized therein, and the size of the currently installed recording paper can be determined by comparing it with the internal data. In this case, if the maximum size paper is A3R, the moving distance of the sensor from the center is 148.5 km, so the CPU
If the on-time is counted using a counter with a resolution of 256 bits at 10I, it becomes possible to detect small-sized paper such as A3 or smaller. FIG. 7 shows a case where the reflective photosensor 6 is moved not only in the X direction but also in the Y direction. As shown in figure (a),
When moving the reflective photosensor 6 only in the X direction, for example, the distance in the X direction is the same for A3R (A3hI feed) and A4 (A4 horizontal feed) or A4R and A5.
The types of recording paper that can be discriminated are limited. Figure (b), (
As shown in C), if the ON time of the sensor is detected in both the X direction and the Y direction, and the combination of these detection times is determined by the CPUl0I, it is possible to detect all types of recording paper sizes. can. The detection device shown in the embodiment of FIG. 1 makes such detection possible. FIGS. 8 and 9 show other embodiments. In the detection device of this embodiment, the reflective photosensor 6 is moved by the moving means along one arcuate trajectory opposite the recording paper 2 through the ends of two mutually orthogonal sides of the recording paper 2 . In such a case, the moving means is set so that one trajectory of the reflective photosensor 6 passes through two edges of all types of recording paper used in the printer. In this embodiment, this moving means is constituted by a motor 8 and a sensor arm 7 attached to the shaft end of the motor 8 and rotated. FIG. 1O (al indicates the trajectory of the reflective photosensor 6 with respect to the various types of recording paper 2 installed. In this trajectory, the reflective photosensor 6 is turned on while the recording paper is at the opposite position. Since this trajectory length differs for each size of paper, the time when the reflective photosensor 6 is turned on also differs for each size as shown in FIG. According to this method, the moving means can be made simple in structure. FIG. 11 shows the detection state of the reflective photosensor 6, and the same figure ( The one shown in a) is of the normal format, and the one shown in the same figure (b)
The one is a condensing sensor. In the normal type sensor shown in Figure (a), the detection range of the opposing surface is 11~lx CQ
t is the distance M) from the sensor position to the bottom 1a of the baker's cent 1;
The detection position depending on the height of the recording paper 2 changes greatly depending on the light emission and light reception range b, and when detecting the recording paper on the bottom surface la of the vapor cassette, variations in detection occur within a maximum range of y. On the other hand, in the condensing type sensor shown in FIG. 6B, the maximum variation in the detection range from 13 to β4 is y2, which is significantly reduced compared to yl of the normal type sensor. Therefore, it is desirable to use a condensing type photo sensor as the reflective photosensor 6. In Figure 12, an optical fiber cable is used for the optical sensor part of the reflective photosensor 6, a condensing lens 6c is provided at the tip of the optical fiber cable 6d, and an LED 6a and a phototransistor 6b are provided at different locations. Give an example. In this way, the optical sensor section can be miniaturized and the detection device can be easily arranged within the printer. Effects As described above, according to the present invention, in the invention of claim 1, the size is detected by moving the reflective photosensor in the width direction from the minimum size to the maximum size of the sheet, so that the paper feed container As well as making it easier to universalize
The simple configuration can reduce the cost of the device. In the invention according to claim 2, in addition to the above, the reflective photosensor is also moved in the sheet feeding direction by the moving means, and this detection signal is also added to the judgment means, so that the judgment is made by the judgment means.
Even if the sheets have the same size in the width direction, it is possible to detect sheets of different sizes, and a wider variety of sheet sizes can be detected. In the invention of claim 3, in addition to the effect of the invention of claim 1, since the reflective photosensor is moved in an arc shape by the moving means to detect the sheet, all sorts of different sizes can be sorted with a -degree movement. The size of the sensor can be determined, which further simplifies the detection device and reduces costs.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a sheet size detection device according to an embodiment of the present invention, Fig. 2(a) is a side view thereof, Fig. 2(b) is a sectional view of a reflective photosensor section, and Fig. 3 is a paper cassette. FIGS. 4(a) and 4(b) are perspective views showing the state in which the
) and FIGS. 5(a) and (b) are explanatory diagrams of the operation of the reflective photosensor. FIGS. An explanatory diagram of a method for detecting the size of recording paper of various sizes, FIG. 8 is a perspective view of a sheet size detection device of another embodiment, FIG. 9 is a side view thereof, and FIG. 1O(a)
, (b) is an explanatory diagram of the sheet size detection method, and Fig. 11 (
a), 0)) is an explanatory diagram showing the detection state of a reflective photosensor, Fig. 12 is an explanatory diagram of a reflective photosensor using an optical fiber cable, and Fig. 13(a) is an example of a conventional detection device. FIG. 2B is a schematic diagram of the shielding plate, and FIG. 1C is a circuit diagram thereof. 1...Paper cassette (paper supply container) 2...Recording paper (sheet) 6-...Reflective photo sensor 7...Sensor arm (transfer means) 8...Motor (movement) means) 9..., drive wire (moving means) 10... pulley (moving means) 101..., CPU (determination means) 1st Akane

Claims (3)

[Claims] (1) In a sheet size detection device that detects the size of a sheet of one size installed at a predetermined position of a paper feed container of an image forming apparatus that can use sheets of multiple types of sizes, opposing positions a reflective photosensor that detects whether or not there is a sheet in the plurality of sizes; and a direction in which the sheets are fed for all of the plurality of sizes from a position opposite to the smallest size sheet among the plurality of sizes of sheets. moving means for moving the reflective photosensor to a position corresponding to a width direction end that is perpendicular to the sheet; and determining a sheet size in accordance with a detection amount detected by the reflective photosensor while the sheet is being moved. A sheet size detection device comprising: a determination means; and a sheet size detection device. (2) The moving means is configured to move all of the sheets of the plurality of sizes from a position opposite to the smallest sheet of the plurality of sizes of sheets in a direction parallel to the direction in which the sheets are fed. The sheet size detection device according to claim 1, wherein the reflective photosensor is moved to a position corresponding to an end in the width direction. (3) Instead of moving the reflective photosensor to an end in the width direction of the sheet, the moving means moves the reflective photosensor to two positions perpendicular to each other on all of the sheets of the plurality of sizes. The sheet size detecting device according to claim 1, wherein the sheet size detecting device moves along one arcuate trajectory passing through the edge of the side and facing the sheet.