JP2005320101A - Rolled paper feeder and image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize the number of detection devices provided for every paper size, to eliminate size setting work by an operator and to prevent erroneous operation of an image formation device due to erroneous detection, in a rolled paper feeder capable of detecting a plurality of paper sizes. <P>SOLUTION: In the rolled paper feeder, the rolled paper is rotatably supported by a pair of flange members detachably provided on both ends of the rolled paper. The rolled paper feeder is provided with a cam provided on an end surface of the flange member; a mirror piece pivoted by the cam, a light source for irradiating the mirror piece with a light; and a sensor for detecting a reflection light by the pivoted mirror piece. The rolled paper size is detected by variation of detection frequency of the reflection light by the sensor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile that uses roll paper as a recording paper, and the size of the paper fed out from one of a plurality of roll papers installed in the paper feed unit, In particular, the present invention relates to a roll paper feeding device that detects the width of a roll paper and an image forming apparatus including the roll paper, and more particularly to an apparatus that can accurately detect the paper size even if the number of sensors is reduced.

An image forming apparatus such as an electronic copying machine is configured to be able to use many sheets of different sizes. A general small-sized electronic copying machine or the like uses a plurality of sizes of paper, and thus a paper size display means is provided for the paper feed cassette. As a means for detecting the size of the paper loaded in the paper cassette, it can be moved within the paper cassette and automatically detects the paper size from the position of the end fence that regulates the paper stacking position. There is. In the case of using small-sized standard paper, information on the paper size can be detected by a side fence provided in the paper feed cassette, but in an image forming apparatus for drawings or the like that uses large-sized roll paper. In many cases, it is difficult to provide such detection means. Therefore, in an image forming apparatus using roll paper, a means for manually setting paper size information for each roll paper is used for each roll paper loaded in the paper feed unit each time the roll paper is loaded. ing.
However, if the operator forgets to enter the paper size information when the roll paper is replaced, the previously set paper size information will remain as it is, and the created copy will be The inconvenience that it becomes not is generated.

Therefore, for a paper feeder that uses a plurality of large-sized roll papers, the paper transport path is provided with paper size detectors as many as the number of paper sizes that can be detected at the position where the side edge of each paper size passes. Is common. However, even in the case of large-size paper used in copying machines, there are two types of paper, A-series and B-series, stipulated by JIS, and the width of the paper is very close to each of these series of paper. There are many things. In order to accurately discriminate between the respective sizes of paper, there is a problem that the sensor must be arranged in a state of being very close to the paper.
If the sensor is disposed close to the paper, the sensor is likely to come into contact with the paper, and the paper may be caught by the sensor. If many sensors are provided close to the paper according to the number of paper sizes that can be detected, the risk of the paper being caught by the sensors becomes even more significant. If a large number of sensors are placed close to each other, when the paper is in an oblique feed state, erroneous detection information may be output from a sensor that does not match the paper size. There is also a problem that the control device of the machine malfunctions.
When the paper size detection device malfunctions, a detection unit disposed on the paper transport path is used to control the exposure device, the development device, etc. of the copying machine according to the detected error information. When information on a paper size different from the information set in the above is detected, there is a problem that the operation of the apparatus is stopped.

In order to solve these problems, Japanese Patent Laid-Open No. 05-105269 provides a means for setting information on whether the A series or the B series in advance, and by combining the information on the paper type and the detection information by the size detection mechanism, There has also been proposed an apparatus that makes it possible to easily specify the paper size and to share the sensors arranged in the paper conveyance path for two series of papers having similar sizes, thereby reducing the number of sensors. .
However, this apparatus cannot cope with all paper sizes distributed in the market, and there is a limit to the size that can be detected. In addition, since switching between the A series and the B series depends on the operator, the occurrence of an erroneous operation cannot be eliminated.

Japanese Patent Laid-Open No. 5-105269

  The present invention has been made in view of the above circumstances, and by proposing a roll paper feeding device capable of detecting multi-stage paper sizes, the number of detection devices conventionally provided for each paper size is minimized. It is an object of the present invention to prevent the image forming apparatus from malfunctioning due to erroneous detection, by eliminating the need for size setting by an operator. It is another object of the present invention to detect not only the paper size but also the end of the roll paper and the remaining amount of paper by the roll paper feeding device.

  In order to achieve the above object, in the first, second, third, and fourth aspects of the invention, a protruding cam provided on the end surface of the flange member that rotatably supports both ends of the roll paper, and the cam swings by the cam. A sheet size, a sheet end, and a remaining sheet amount can be detected by a mirror piece, a light source that emits light toward the mirror piece, and a sensor that detects reflected light from the oscillating mirror piece. With this configuration, the relationship between the detection time of the reflected light by the sensor and the paper size is continuously supported, so that the paper size can be detected in multiple stages, and the number of detection devices can be reduced. It is characterized in that the reliability of detection can be improved.

  According to a fifth aspect of the present invention, in the roll paper feeding device according to any one of the first to fourth aspects, the swing speed of the mirror piece is different between the forward movement and the backward movement. .

  According to a sixth aspect of the present invention, in the roll paper feeding device according to any one of the first to fifth aspects, the rotational speed of the mirror piece is greater in the backward movement than in the forward movement. Features.

  According to a seventh aspect of the present invention, in the roll paper feeding device according to any one of the first to sixth aspects, an LED is used as a light source.

  The invention according to claim 8 includes the roll paper feeding device according to any one of claims 1 to 7 in the image forming apparatus, so that no size input by the operator is required. It is characterized in that erroneous detection of the paper size is eliminated and image formation on paper that does not fit the original can be prevented.

  According to the present invention, since the detection time of reflected light that varies depending on the paper size can be continuously viewed, there is no need to provide a detection means for each size as in the past, and the detection size is detected finely. And the number of detection devices can be reduced. Therefore, the switching operation of the A row and the B row as in the conventional example is not necessary, and the malfunction of the image forming apparatus due to a size switching operation error can be prevented. In addition, the detection time of the signal input to the detection unit twice per cycle due to the swing of the reflection plate can be determined by changing the reciprocating speed of the reflection plate. The state of the reflector can be determined from the signal. This eliminates assembling errors due to an increase in parts and improves reliability.

FIG. 1 is a schematic diagram showing an example of an image forming apparatus such as a copying machine to which the present invention is applied. A drawer-type paper feed tray 1 for setting the roll paper 2 is provided at the bottom of the apparatus. The roll paper 2 can be set from above or from the front with the paper feed tray 1 pulled out. ing.
The roll paper 2 is fitted with a flange member 3 shown in FIG. 2 at both ends of the paper tube which is the core shaft, and the flange member 3 is rotatably mounted on the receiving table 4 on the paper feed tray 1. After the end of the paper drawn from the roll paper 2 is held by the feed roller pair 5, the paper feed tray 1 is pushed into the apparatus to finish the roll paper setting. The roll paper is drawn out and conveyed by the feed roller pair 5. A known cutter unit 6 such as a rotary type or a rotary tooth slide type is provided near the exit of the conveyance path inside the tray, and the roll paper 2 is cut to a predetermined length intended by the apparatus main body.

The paper that passes through the cutter unit 6 and is cut to a predetermined length passes through a paper conveyance path inside the apparatus main body, is synchronized with the image formation timing by the registration roller 7, and is transferred from the photosensitive member 26 by the transfer unit 8. After the toner image is transferred and thermally fixed by the fixing unit 9, the toner image is discharged to the paper discharge tray 27.
In the document reading unit 10, the document is conveyed and read by an automatic document feeder (ADF), and the photosensitive member 26 is exposed. The apparatus of FIG. 1 includes an upper tray 28 configured to set two roll papers in addition to the paper feed tray 1 which is a lower tray for setting one roll paper. The upper tray 28 has the same configuration as that of the paper feed tray 1 except that two roll papers share the cutter unit 6 and supports each roll paper.

  As shown in FIG. 2, the cradle 4 that supports both ends of the roll paper 2 via the flange portion 3 has a pair of rollers 17 that rotatably support the flange portion 3 on its upper portion. A pair of boss portions 12 are provided on the bottom surface. On the other hand, the paper feed tray 1 is provided with a bottom plate 11 for placing and supporting the receiving tray 4. The bottom plate 11 is provided with positioning holes 13 that fit into the boss portions 12 provided on the lower surface of the cradle 4 so as to correspond to the standard size of the roll paper 2 to be used side by side in the axial direction of the roll paper. It has been. A magnet 14 is provided on the bottom surface of the cradle 4. On the other hand, the bottom plate 11 is formed of an iron material, and the cradle 4 positioned by the positioning hole 13 is attracted and fixed to the bottom plate 11.

In FIG. 4, the flange members 3 provided at both ends of the paper tube of the roll paper 2 are configured by a flange portion 16 and a support cylindrical portion 15 that is inserted into and fixed to the paper tube of the roll paper 2. By receiving the flange portion 16 with the roller 17, the roll paper 1 can be freely rotated as described above.
In a state where the roll paper 2 is mounted on the box-shaped cradle 4, the outer wall surface 30 that overlaps the lower portion of the flange portion 16 of the cradle 4 has a strip-like shape whose one end is supported by a vertical axis 31 so as to be swingable. A mirror piece 19 is provided. The mirror piece 19 is given a biasing force of the leaf spring 21 so as to maintain the same position as the outer wall surface 30.

  On the other hand, six triangular projections 18 as cams are provided on the end surface of the flange portion 16 along the circumference, and these projections are formed on the roll paper 2 as shown in FIG. Along with the rotation of the flange portion 16 when being pulled out by 5, the mirror piece 19 is brought into contact with the protrusion 20 provided on the back surface of the mirror piece 19, so that the mirror piece 19 is flush with the outer wall surface 30. Oscillating intermittently between the second position inclined with respect to the outer wall surface 30.

  On the side plate 32 that rises from the bottom plate 11 of the paper feed tray 1 and faces the outer wall surface 30 of the cradle 4, a vertically long slit 24 that faces the mirror piece 19 is formed. A light source device 33 including a light source 22 that irradiates the mirror piece 19 through the slit 24 and a condensing lens 23 that converts the light from the light source 22 into parallel light is provided on the outer surface of the side plate 32. Due to the swinging motion of the mirror piece 19 accompanying the rotation of the flange portion 3, the reflected light from the mirror piece 19 scans the inner surface of the side plate 32 in the range of an angle θ that is twice the swing angle of the mirror piece 19. In the reflected light scanning range on the inner surface of the side plate 32, a light receiving element 25 as a sensor for detecting reflected light is disposed.

  The mirror piece 19 swings from a first position that is coplanar with the outer wall surface 30 to a second position that is inclined with respect to the outer wall surface 30, that is, a position that is inclined at an angle θ / 2 with respect to the first position. The moving time is set longer than the backward moving time for swinging from the second position to the first position. The long / short relationship between the forward movement time and the backward movement time can be obtained by appropriately determining the shape of the protrusion 18 as the cam of the flange portion 16 or the protrusion 20 of the mirror piece 19 or both the protrusion 18 and the protrusion 20. . By using white LED light with high brightness as the light source 22, high brightness and low power consumption efficiency can be achieved without using a halogen lamp that has a low lifetime as in conventional filament spheres. It can be a good system.

FIG. 5 shows the detection state of the reflected light from the reciprocating mirror piece 19 by the light receiving element 25 and the positional relationship of the mirror piece 19 in time series. The right direction is the time passage direction. In the figure, “a” indicates the swing period of the mirror piece 19. Actually, there is a time lag in the detection start time depending on the installation position of the light receiving element 25, and the period thereof is f. Here, of course, a = f. During one cycle in which the mirror piece 19 reciprocally swings, the reflected light is detected twice when it moves to the right and to the left in the figure. As described above, the forward movement time b for the mirror piece 19 to swing from the first position to the second position is set longer than the backward movement time c for swinging from the second position to the first position. Therefore, when the detection time when the mirror piece is moved forward by the light receiving element 25 is d and the detection time when the mirror piece is moved backward is e, d> e.
In this embodiment, the time g from the time when the reflected light is detected when the mirror is moved to the right when the reflected light is detected when the mirror is moved to the time when the reflected light is detected when the mirror is moved backward is calculated. The paper width can be calculated by applying the value of f to the paper width relational expression which is the size in the paper width direction. Further, since d> e, the detection of the reflected light during the forward movement and the backward movement of the mirror piece is clearly distinguished, and the detection interval g is accurately detected. If d = e, the order of d → e → d → e... Continuously detected becomes uncertain. To avoid this, at least another light receiving element is provided. It is necessary to clarify the reciprocal relationship of reflected light. The magnitude relationship between the detection times d and e during this mirror piece reciprocation may be e> d.

  FIG. 6 is a schematic diagram when the paper width is detected. The moving range of the reflected light on the side plate 32 by the mirror piece is longer in the roll paper R1 between the roll paper R1 having a narrow width and the roll paper R2 having a wider width, and therefore the time g1 in the case of the roll paper R1. Is longer than g2 in the case of the roll paper R2. Therefore, the value of g / f varies uniquely according to the paper width. When transporting roll paper, this value can be determined if at least one period of time can be measured. Therefore, the applicable range is wide and can be detected in multiple stages using a combination of a set of light emitting elements and light receiving elements, thereby reducing the number of detection devices. Can improve reliability.

  FIG. 7 shows a correlation example between the g / f value and the paper width. Although the example of detection is shown in four steps in the figure, since one value is always shown for the paper width, multi-step detection can be performed as necessary. This g / f value does not depend on the rotation speed of the roll paper, and the g / f value does not change even if a change occurs in the rotation speed.

  FIG. 8 shows an example in which the above-described roll paper width detection devices are provided on both sides of the roll paper set in the paper feed tray 1. As shown in FIG. 8A, when the set position of the roll paper on the paper feed tray is the center reference, the detection results (g / f values) from both sides of the roll paper are recognized as the same. However, if the roll paper to be set on the paper feed tray with the center reference is set on one side reference as shown in FIG. 8B, the detection results (g / f values) from both sides of the roll paper are different from each other. Therefore, by comparing the detection results, it is possible to easily determine whether the roll paper setting position is correct, and it is possible to prevent a roll paper loading operation error. For example, in the case of a digital copying machine, it is possible to adjust the writing position in the main scanning direction based on the result detected in this way, and to cope with an operation error. If such a mechanism is used, a free setting in which the lateral setting position is not strictly defined is possible, which increases the degree of freedom in operability.

Assuming that the speed at which the paper is drawn from the roll paper by the feed roller is constant, the detection period f accompanying the rotation of the roll paper is gradually changed according to the change in the radius of the rotating roll paper, that is, depending on the remaining amount of the roll paper. Change. The roll paper end can be detected by utilizing the change in the detection cycle f.
FIG. 9 shows a situation in which f gradually decreases during rotation of the feed roller. At the roll end, the value of f changes as follows. If the trailing edge of the paper is glued to the paper tube and does not peel off while the feed roller is rotating, the rotational speed suddenly increases immediately after the paper tube is no longer wound. On the other hand, when the rear end of the paper is free with respect to the paper tube, the rotation of the paper tube gradually slows and stops immediately after the winding is stopped.

  Normally, the detection period f changes gradually and continuously without decreasing as the roll paper rotation radius decreases. Therefore, when the detection cycle f one cycle before is fb and the present time is fn, if the difference is 5% or more, that is, | fb−fn | / fn × 100 ≧ 5, rapid speed fluctuation = end detection Judgment will be made. In this manner, the end of the roll paper can be detected based on the detection information of the reflected light. By applying the roll paper width detection means to the roll paper end detection, the number of parts can be reduced and the cost can be reduced by omitting the roll paper end detection means that has been conventionally provided.

An example of detecting the remaining amount of roll paper by the roll paper width detecting means will be described with reference to FIG.
Since the detection cycle f fluctuates in association with a change in the rotation speed of the roll paper depending on the remaining amount of roll paper, the changing detection cycle f is represented by a correlation curve with the remaining roll paper in the graph of FIG. By applying, it is possible to estimate the approximate remaining amount of roll paper.
As described above, it is possible to effectively perform the roll paper width detection, the roll paper end detection, and the roll paper remaining amount detection by detecting the reflected light from the mirror piece that swings with the rotation of the roll paper as described above. It has excellent effects such as reducing the number of parts.

  Although the present invention has been specifically described above based on the preferred embodiments of the present invention, the present invention is not limited to the detection means described above, and it is needless to say that various modifications can be made without departing from the scope of the present invention. . For example, in the embodiment, the roll paper cradle 4 is installed by the boss portion 12 and the positioning hole 13 on the paper feed tray. This can be arbitrarily set by combining a known rack and pinion. It can also be made movable to the size position. The shape of the protrusion 18 provided on the flange 16 and the shape of the protrusion 20 provided on the mirror piece 19 is not limited to a triangle, but may be any shape as long as the opening time and the closing time of the mirror piece 19 are different. Does not matter. Further, if the number of protrusions 18 formed on the flange portion 16 is increased, the sensor detection cycle f is shortened, and the resolution of the detection portion can be increased accordingly.

1 is a schematic view of a main body of an image forming apparatus such as a copying machine for carrying out the present invention. It is a perspective view which shows the principal part of the roll paper mounting apparatus in this invention. It is a side view of the roll paper mounting apparatus in this invention. It is a top plane schematic diagram showing the principal part of the reflected light detection mechanism in the present invention. It is a time-series figure which shows the positional relationship of the detection signal by the sensor of reflected light, and a mirror piece. It is the schematic which shows the mode at the time of the paper width detection in this invention. It is a correlation diagram of g / f value and paper width. It is the schematic which shows the Example which provided the reflected light detection mechanism in this invention in the both ends of roll paper. It is a figure which shows the change of the detection period f of the reflected light at the time of rotation / stop of roll paper. FIG. 6 is a correlation diagram between a detection period f of reflected light and a remaining amount of roll paper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper feed tray 2 Roll paper 3 Flange member 4 Receiving base 11 Bottom plate 12 Boss part 13 Positioning hole 16 Flange part 18 Protrusion 19 Mirror piece 20 Projection part 21 Plate spring 22 Light source 25 Light receiving element

Claims (8)

  In a roll paper feeding device that rotatably supports the roll paper by a pair of flange members that are detachably provided at both ends of the roll paper, a cam provided on an end surface of the flange member, and swinging by the cam A roll paper feeding device comprising: a mirror piece; a light source that emits light toward the mirror piece; and a sensor that detects reflected light from the oscillating mirror piece.   2. The roll paper feeding device according to claim 1, wherein the roll paper size is detected by a change in a detection period of reflected light by the sensor.   2. The roll paper feeding device according to claim 1, wherein the roll paper end is detected based on a detection period of reflected light by the sensor, which changes in accordance with a decrease in the rotation radius of the rotating roll paper. Feeding device.   2. The roll paper feeding apparatus according to claim 1, wherein the remaining amount of the roll paper is detected based on a detection period of reflected light by the sensor, which changes in accordance with a decrease in the rotation radius of the rotating roll paper. Feeding device.   5. The roll paper feeding device according to claim 1, wherein a swing speed of the mirror piece is different between forward movement and backward movement. 6.   The roll paper feeding device according to any one of claims 1 to 5, wherein the swing speed of the mirror piece is larger in the backward movement than in the forward movement. Paper device.   The roll paper feeding device according to any one of claims 1 to 6, wherein the light source is an LED. An image forming apparatus comprising the roll paper feeding device according to claim 1.

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