JP2002193486A - Paper surface height detecting device in printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a work load of a user by attaching a device for detecting an upper paper loading limit and a device for detecting a residual paper amount in a printer. SOLUTION: The upper paper loading limit and the residual paper amount are detected by attaching an arm or a roller 15 capable of detecting a paper surface height to a printer body or a paper feeding cassette.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper height detecting apparatus capable of detecting the upper limit of the paper stacking amount of a printer using an electrophotographic process and sequentially detecting the remaining amount of paper stacking, and also serving as a paper transport guide. It concerns the device.

[0002]

2. Description of the Related Art In a printer using an electrophotographic process, even when the number of papers is larger than a specified value, the possibility of causing a paper feeding failure or paper jam increases. For this reason, the printer is provided with a sensor for detecting the absence of paper and a display member for notifying the upper limit of the paper stack.

Before describing the state of the sensor, a paper feed cassette for inserting paper into a printer will be described. There are the following two types of paper cassettes. The first method is to lift the set paper to a paper feeding point. This method includes a method of lifting the entire paper and a method of lifting only the paper feeding point side by a spring or the like. After the paper feed cassette is inserted into the printer main body, the whole or a part of the paper is lifted to perform the paper feed operation. This method includes a nail separation method and the like. The second is a method in which the paper is not lifted, and this method includes a slope separation method and the like. By performing separation on a slope, there is no need to fix the paper feed point, and even when the remaining amount of paper is low, paper can be fed without lifting the paper.

[0004] The paper loading upper limit display is a method of lifting paper,
The same method is used for both lifting and non-lifting methods. FIG.
FIG. 6 shows an example of a conventional paper stack upper limit display. (A) is an example in which a projection is provided on the rear end regulating plate to display the upper limit of loading, (b) is an example in which the upper limit of loading is displayed by sticking a sticker on the inner surface of the sheet cassette, and (c) is an example. This is an example in which the upper limit of the stacking is directly engraved on the inner surface of the sheet cassette and displayed. Regardless of the type of cassette, when the paper is set, the bottom of the paper touches the bottom of the cassette, or the top of the paper indicates the amount of paper loaded by pressing down from the top of the paper For this reason, the upper limit of the paper stack can be represented by attaching a member serving as a measure of the height to a position that becomes the upper surface of the paper. As described above, the upper limit of the paper stack is specified in the vicinity of the paper stacking position in the paper feed cassette, and the user is alerted, thereby preventing the stacking of the paper having the upper limit.

[0005]

A paper stacking upper limit value display method generally used in a printer is a method in which a sticker is attached around a paper stacking position (inner side) in a paper feed cassette or is indicated by a projection or the like. Often have been. The user makes a judgment based on this display, and prevents the user from loading more than the upper limit of the load. In these cases, if the sheet is fed after the sheet cassette is sufficiently pulled out or pulled out of the main body, the upper limit of the sheet stacking can be confirmed without any problem. However, in a paper loading operation in a state where the cassette is pulled out halfway or in a dark place, there are cases where it is difficult to see and use the paper. In some cases, it is displayed at a position that is difficult to see in the first place. Such a situation is not very good in usability.

An object of the present proposal is to mount a paper height detecting sensor on a paper cassette or a printer body so that a paper stacking upper limit display can be more easily understood for a printer having a paper cassette. The upper limit is determined, thereby making it possible to prevent a paper feed failure or paper jam due to overloading. At the same time, it is possible to sequentially detect the remaining amount of paper reduced by use of the printer, and to use it as a transport roller using a rotating unit attached to the tip of a paper stack upper limit detection sensor.

[0007]

A first means relating to this proposal is that an up-and-down movable arm-shaped member having a rotatable cylindrical member attached to a tip thereof is lowered from the printer body onto the paper surface. It is characterized by being. This allows the paper cassette to be pulled out halfway from the main unit and loaded with paper.
The paper stacking is performed while pushing up the arm that can move up and down, and the upper limit of the paper stacking can be determined by detecting the paper surface height, and the remaining amount of paper can be sequentially detected. Also, a rotatable circular member at the tip of the arm can be used as a transport roller during paper transport.

A second means according to the present invention is characterized in that a stopper is provided in the paper feed cassette with respect to the first means, so that the paper feed cassette is locked halfway when being pulled out from the main body. I do. As a result, it is possible to always detect the paper surface height at the same position. When releasing the lock, the paper feed cassette can be completely pulled out from the main body by pulling out the paper feed cassette while pressing the lock release button provided on the side of the main body.

A third means according to the present invention is characterized in that the arm is fixed to the main body with respect to the first means, and a freely rotatable elliptical member is installed there. Accordingly, the height of the paper surface can be detected by the change in the angle of the elliptical member when the paper is loaded, and therefore, the detection of the upper limit of the paper loading and the sequential detection of the remaining amount of paper can be performed. By attaching a freely rotatable transport roller to the elliptical member, it can be used as a paper transport member.

A fourth means according to the present invention is characterized in that a vertically movable rotary member is provided in the sheet cassette so that the stacking height can be determined. As a result, it is possible to detect the upper limit of the paper stack in both the state where the sheet cassette is partially removed from the printer main body and the state where the sheet cassette is completely removed, and the remaining amount of paper can be sequentially detected.

A fifth means relating to the present proposal is characterized in that an angle-changeable arm for judging the height of the paper surface when the paper is loaded is installed in the paper feed cassette. As a result, it is possible to detect the upper limit of the paper stack in both the state where the sheet cassette is partially removed from the printer main body and the state where the sheet cassette is completely removed, and the remaining amount of paper can be sequentially detected.

A sixth means relating to the present proposal is to install a unit which can be moved up and down according to the height of the paper surface on a rear end regulating plate of the paper feed cassette so that the unit comes into contact when the paper reaches the upper limit. A terminal is installed, the upper limit of the paper stack is detected by contact of the terminal, and the information is notified to the main body by a radio wave. For the sequential detection of the remaining amount of paper, a light source and a light receiving element are installed on the printer body, and a reflection plate is attached to the paper upper limit detection unit of the rear end regulating plate, and the light emitted from the main body light source is reflected by the reflection plate. It is characterized in that the remaining amount of paper is sequentially detected by detecting it with a light receiving element. As a result, it is possible to detect the upper limit of the paper stack in both the state where the sheet cassette is partially removed from the printer main body and the state where the sheet cassette is completely removed, and the remaining amount of paper can be sequentially detected.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) In a first embodiment, when a paper feed cassette is pulled out of a printer main body halfway and paper is loaded, the height of the paper surface is set by an arm installed in the main body. Is monitored to detect the paper stack upper limit. This makes it possible to reduce the work of checking the upper limit of the load that has been performed by the user. Further, by monitoring the height of the paper surface, the remaining amount of paper is sequentially detected, and a rotatable member is provided at the end of the arm to enable use as a transport roller.

FIGS. 1 to 4 show the structure of this embodiment. 1 is a cross-sectional view of the printer main body (when the paper cassette is inserted), FIG. 2 is an enlarged view of the paper cassette section, FIG. 3 is a cross-sectional view of the printer main body (half the paper cassette is taken out), and FIG. 4) is an enlarged view of the paper surface height detection sensor unit as viewed from the side, and FIG. 4B is an enlarged view of the paper surface height detection sensor unit as viewed from the front. 11 is a printer body, 12 is a paper cassette, 13 is paper, 14a
Is a paper feed roller, 14b is a main body relay roller, 15 is a paper surface height detection sensor, 16 is a paper transport path, 17 is a rear end regulating plate, 1
8a to 18d are holes for a photo height detecting photo sensor,
e is a hole for the photo sensor for detecting the upper limit of the load, and 19 is a photo sensor.

The upper limit of the paper stack is displayed by a method of attaching a sticker to the inner surface of the paper stack position in the paper feed cassette or forming an irregular shape. In this case, when the paper cassette is sufficiently pulled out or loaded from the main body, the upper limit of the loaded paper can be confirmed without any problem. However, when the paper loading operation is performed in a state where the cassette is partially removed, or when the paper loading operation is performed in a dark place, it is very hard to see and use. In some cases, it is displayed at a position that is difficult to see in the first place. Such a situation is not very good in usability.

Therefore, in order to automatically determine the upper limit of the paper stack, an arm that can move up and down is installed on the upper surface of the cassette insertion portion of the main body. When loading paper, the paper cassette is pulled out of the main body partway, paper is set in the paper cassette, and the height of the paper surface at that time is detected. In this embodiment, a photo sensor is used as a detection method. The arm is passed through a square cylinder with a plurality of holes on the side, so that the holes are blocked by changes in the height of the arm. 4 in FIG.
Photosensors are arranged in all the holes a to 18e, and the holes that are closed as the paper load increases are monitored. When the amount of paper increases due to paper loading, the hole 18a is first closed.
At this time, since the optical path of the photo sensor is interrupted, 18a
It can be confirmed that there is a space in the state of. Further, as the amount of paper further increases, the paper is closed at 18b, 18c, and 18d, and when the amount of paper reaches 18e, the paper load upper limit sensor determines that the paper is NG. In this embodiment, as a means for transmitting the determination result to the user, a display panel provided in the printer main body indicates that the paper height is the upper limit. In addition, the process of printing and decreasing the amount of paper is detected at any time, and similarly, the remaining amount of paper is sequentially detected by sequentially displaying the remaining amount of paper on the main body display panel. In addition, a freely rotatable member at the tip of the paper surface height detection sensor is installed, and the rotation of the member is used as a transport roller to reduce the load during paper transport.

As described above, by detecting the paper surface height during the paper stacking operation and notifying the user when the height exceeds the upper limit, the work of checking the upper limit of the stack which has been performed by the user can be reduced. The paper loading operation can be performed smoothly. In addition, the apparatus can detect the height of the paper surface at any time, so that the remaining amount of paper can be sequentially detected. By installing a freely rotatable member, the apparatus can be used as a transport roller.

(Second Embodiment) The second embodiment is different from the first embodiment in that when the paper cassette is pulled out of the main body partway and the paper is stacked, the paper cassette is locked once. In this manner, the paper cannot be extracted, and the paper stacking operation is performed there. When completely pulling out the paper cassette from the main body, it is possible to completely remove the paper cassette by pulling it out while pressing the button on the side of the main body for unlocking.

The construction of this embodiment is shown in FIGS. FIG. 5 is a sectional view of the printer main body (at the time of paper stacking operation), and FIG. 6 is an enlarged view of a cassette lock release button. Basically, it is the same as the first embodiment, except that a stopper is provided so that when the paper cassette is pulled out halfway from the printer main body, the paper cassette is locked so as not to be pulled out further.
When completely pulling out the paper cassette from the printer body, the paper cassette is pulled out while pressing the lock release button 21.

As in the first embodiment, when loading paper in the paper feed cassette, the height of the paper surface is detected by an arm installed on the main body, and thereby the upper limit of the paper loading is detected. At this time, if the paper feed cassette is completely extracted or if the paper cassette is excessively extracted, the location of the paper surface height detection sensor becomes a place where no paper exists. In this case, the paper surface height cannot be detected, and the effect of the first embodiment cannot be obtained. For this reason, a stopper is installed on the paper cassette so that the paper height detection sensor stops at the position where paper is present when the paper cassette is removed from the main body, and the paper cassette is locked at that position so that it can not be pulled out further. To By doing so, the printer main body and the paper feed cassette always come to the same position during the paper stacking operation, and the effect of the first embodiment can be always obtained, thereby reducing the burden on the user. In this embodiment, when the paper height detection sensor detects the upper limit of the stacking by the paper stacking operation, this embodiment notifies the user by lighting a stacking upper limit warning lamp installed beside the display panel at the top of the main body. After the paper stacking operation is completed and the paper cassette is inserted into the printer main body, the arm operates as a device for sequentially detecting the remaining amount of paper. As the amount of paper decreases, the position of the paper surface height detection sensor lowers, and by monitoring this, it is possible to sequentially detect the remaining amount of paper. The detected remaining amount of paper is displayed on the main body display panel at any time. A freely rotatable member is installed at the end of the paper height detection sensor, and the rotation is used as a transport roller.

As described above, when the paper cassette is pulled out of the printer main body, by locking the paper cassette so that it cannot be pulled out more than necessary, it is possible to detect the upper limit of the paper loading accurately, thereby smoothing the paper loading operation. Can be performed.

(Third Embodiment) In a third embodiment, an arm from the main body is fixed to the first embodiment, and an elliptical member whose angle changes at the tip of the arm is installed. The paper stacking amount is detected based on a change in the angle of the member. After the paper is loaded, the curve of the elliptical member is used to secure the paper transport path and reduce the load during paper transport.

FIG. 7 shows the configuration of this embodiment. (A) shows the movement of the elliptical member when the paper is fully loaded, (b) shows a state where it is almost half empty, and (c) shows the movement of the elliptical member when there is no paper. Reference numeral 12 denotes a paper cassette, 13 denotes paper, 14a denotes a paper feed roller, 14b denotes a main body relay roller, 15 denotes a paper surface height detection sensor, 17 denotes a rear end regulating plate, and 31 denotes a transport roller.

In the first embodiment, the height of the sheet is detected by the vertical movement of an arm installed on the main body. On the other hand, in the present embodiment, the paper surface height is detected by changing the angle of the elliptical member attached to the arm. The arm is fixed to the main body, and does not move up, down, left, right, or change the angle. An elliptical member is attached to the tip of this arm with its center shifted, so that the angle changes depending on the paper loading. By loading paper, the lower side of the elliptical member is pushed, and the angle between the major axis of the elliptical member and the paper changes. By monitoring the angle change, the height of the paper surface is detected. As a detection method, a rotary switch that can be switched in multiple steps is attached to the elliptical member, and the printer body side detects the position of the switch due to the angle change of the elliptical member, and detects the paper height I do. In this embodiment, a warning sound is emitted using a speaker installed in the main body to notify the user as a communication means to the user when the upper limit of the paper stack is detected. After the paper stacking is completed and the paper cassette is inserted into the main body, the remaining amount of paper is sequentially detected using this arm. Since the height of the paper surface can be monitored by detecting which part of the rotary switch is located, the information is displayed on the display unit of the main body and the remaining amount of paper is sequentially detected. . In order to detect the paper-out state, the elliptical member is made to protrude from the lower end of the cassette when the paper runs out. With such a structure, it is possible to distinguish between a state in which even one sheet of paper is present and a state in which no paper is present.

The curved portion of the elliptical member is used as an auxiliary member for paper conveyance. The rotation speed of the main body relay roller is designed to be slightly higher than the rotation speed of the paper feed roller. For this reason, when the gap between the cassette wall surface and the elliptical member is small, the tension force is always in the working state, which may cause the paper surface to be damaged. In order to avoid this, the elliptical member at the tip of the arm is set so as to keep a certain gap with respect to the transport guide on the cassette wall. Immediately after being drawn into the main body relay roller, the paper is located on the wall surface side and the drawing speed is high as the paper is drawn, so that the paper approaches the elliptical member. At this time, rubbing resistance is generated at a portion where the elliptical member comes into contact with the paper. In order to reduce this, a rotatable roller is provided on the elliptical member. The rollers reduce sliding friction resistance during paper conveyance, thereby enabling smooth paper conveyance. When this elliptical member is used for paper conveyance, when the paper end is pulled in by the main body relay roller, a force acts to push up the front side of the elliptical member by the tension of the paper, and this effect pushes down the rear side. Because the force works, it is possible to hold down the paper.

By attaching the elliptical member whose angle changes to the tip of the arm on the main body, the height of the paper surface is monitored,
It can be used to detect the paper stack upper limit and the remaining amount of paper successively, and can be used as a paper transport auxiliary member by using the curved portion of the elliptical member.

(Fourth Embodiment) In a fourth embodiment, a paper stacking upper limit detection sensor is installed in a paper feed cassette, and when the paper is set in the paper feed cassette, the sensor is set while pushing up the sensor unit. The height of the paper surface can be detected by gradually raising the sensor unit according to the amount of paper set. In this case, the paper stacking upper limit can be detected not only when the paper cassette is partially removed from the printer main body but also when the paper cassette is completely removed. After the paper is loaded, it can be operated as a paper remaining amount detection sensor.

FIGS. 8 to 10 show the structure of this embodiment. 8 is a view of the paper feed cassette as viewed from above, FIG. 9 is a sectional view of the paper feed cassette, and FIG. 10 is a view of the paper feed cassette as viewed from the side. 15 is a paper height detection sensor, 41
Is a paper surface height display section, and 42 is a spring. The paper height is detected by a paper height detection sensor, and the paper height is displayed on a display unit disposed in front of the paper feed cassette through two members on the side of the paper feed cassette.

When the paper is set in the paper feed cassette, if the stacking upper limit detection sensor is in the printer main body, it can be detected only when the paper feed cassette is pulled out of the main body partway. However, in this method, when the paper cassette is completely removed from the printer main body and the paper is set, the paper stack upper limit cannot be detected. In order to solve this, a paper height detection sensor is installed on the paper cassette side. When the paper is loaded, the paper height detection sensor rises accordingly, and the display on the front surface of the cassette fluctuates accordingly. As a display method, there are various methods such as a display using a display panel and a display using a gauge using an LED or the like, in addition to a method of displaying using a mechanical device. A method using a mechanical device that can be manufactured is adopted. The paper loading upper limit is displayed on the display unit, and the paper loading is continued until this state is reached. After the paper stacking is completed and the cassette is inserted into the main body, the paper surface height detection sensor operates as a sensor for sequentially detecting the remaining amount of paper, and a change in the remaining amount of paper is sequentially displayed on the display unit on the front of the cassette.

By installing the paper height detecting sensor in the paper feed cassette in this way, it is possible to detect the upper limit of the paper stack even when the paper feed cassette is partially pulled out from the main body or when it is completely pulled out. Can be. Further, similarly to the above-described embodiment, since the height of the stacked paper is detected, the remaining amount of paper can be sequentially detected.

(Fifth Embodiment) In a fifth embodiment, an arm-shaped paper stack upper limit detection sensor movable forward and backward is installed in a paper feed cassette, and the change in the angle of the arm when paper is stacked in the cassette is detected. The upper limit of the load is determined by detecting the load. The angle of the arm gradually changes according to the amount of paper set. This change is monitored and the user is notified when the upper limit of the paper stack is reached.

FIGS. 11 to 11 show the structure of this embodiment.
As shown in FIG. 11 is a paper height detection sensor unit, FIG. 12 (a) is a cross-sectional view of a paper cassette (no paper), FIG. 12 (b) is a cross-sectional view of a paper cassette (paper full state), and FIG. It is an enlarged view of a detection sensor. Reference numeral 15 denotes a paper height detection sensor, and reference numeral 51 denotes an angle detection sensor. The operation of the 15 sheet height detection sensor and the operation of the 51 angle detection sensor are linked, and the angle change of the sheet height detection sensor is read by the angle detection sensor.

An arm-shaped member is attached to the sheet cassette, and the height of the sheet is detected based on a change in the angle. By loading paper, the angle of the arm gradually changes. An angle detection sensor is attached to the arm whose angle changes, and when the paper stacking upper limit is reached, the angle is detected, and a warning sound is emitted to inform the user. Angle detection is performed by attaching a member that moves in conjunction with the arm, and attaching a photosensor in a range where the member changes due to a change in the angle of the arm. When the angle due to the paper stacking is within the range of the stacking upper limit detection sensor, a warning sound is emitted from a speaker installed in the cassette to notify the user. A battery is mounted on the paper cassette as a power source for the angle detection sensor and the speaker, and is charged based on the power supplied from the main body when the printer is inserted into the main body. At this time, charging terminals are installed on the cassette and the main body, and the charging terminals are joined when the cassette is inserted into the main body.

Further, by detecting from the angle when the paper is fully loaded to the angle when there is no paper by the angle detection sensor, it is possible to sequentially detect the remaining amount of paper. A prism having a plurality of holes (18a to 18e) is attached to the angle detection sensor, and photo sensors are installed in all the holes. The angle of the angle detection sensor changes according to the amount of paper loaded, and this is detected. When no paper is loaded, the holes are not closed, and the paper is sequentially closed from 18a as the paper is loaded. In this method, light does not pass through when the hole is closed, so that the current paper height can be known by specifying the number of the photosensor that has not detected light. When the paper stacking progresses and reaches the upper limit of the stack, the hole of the sensor for detecting the upper limit of the stack is closed, and the upper limit can be known because the detection is performed by the photo sensor. The detected information is transmitted to the main body, and a report of the upper limit of the paper stack is made on the main body display. When printing is performed and the remaining amount of paper is reduced, the remaining amount is sequentially displayed. As a method of transmitting the data from the cassette to the main body, a data transfer terminal is provided near the charging terminal, and information on the remaining amount of paper is transmitted to the main body using the terminal.

By installing the paper height detecting sensor in the paper feed cassette in this manner, it is possible to detect the upper limit of the paper stacking even when the paper feed cassette is partially pulled out from the main body or when it is completely pulled out. Can be. Further, as in the above-described embodiment, by monitoring the paper surface height, the remaining amount of paper can be sequentially detected.

(Sixth Embodiment) In a sixth embodiment, a unit is provided in which a terminal is attached so that it can be detected by contacting the rear end regulating plate inside the paper feed cassette when the paper stacking upper limit is reached. Is installed, and when the paper stacking upper limit is reached, the terminals are brought into contact with each other to conduct electricity, thereby detecting the stacking upper limit and transmitting it to the main body by radio waves. In addition, a reflection plate is attached to the unit installed on the rear end regulating plate to reflect the light radiated from the light source installed in the main body, and it is detected by the light receiving unit installed in the main body, so that the remaining amount of paper is sequentially determined. That is, detection is performed.

FIG. 14 shows the structure of this embodiment.
As shown in FIG. FIG. 14 is a sectional view of the printer main body, and FIG.
15A is a cross-sectional view of the paper feed cassette (when paper is fully loaded), FIG.
FIG. 2B is a cross-sectional view of the paper feed cassette (when there is no paper). 6
1a is a light emitting element, 61b is a light receiving element, 62 is a reflector, 6
3 is a terminal for a paper loading upper limit detection sensor, 64 is a radio transmitter,
65 is a radio wave receiver.

In this embodiment, a paper height detecting unit which can be moved up and down according to the paper height is installed on the rear end regulating plate.
The height of the paper surface is detected by moving the unit up and down. The paper surface height detection unit has a shape in which the paper insertion side is lifted, so that the paper surface height detection unit smoothly rises when paper is set. Install a terminal on the back side of the rear end regulating plate so that it contacts when the paper load reaches the upper limit, attach an electrode to this terminal, monitor the conduction by contacting the terminal, and set the upper limit of the paper load. Can be detected.
When the upper limit of the stacking is detected, information is transmitted to the main body from a radio wave transmitting unit attached to the sheet cassette. On the main unit side, the signal is received by the receiving unit, and the user is notified of the upper limit by the main unit display unit. A battery is mounted on the paper cassette side to supply power to the paper loading upper limit detection terminal and the radio wave transmitter. Then, the battery is charged from the main body side when inserted into the main body. For this purpose, terminals are attached to the sheet cassette and the main body, respectively, so that the terminals come into contact when the sheet cassette is inserted. Power is supplied from the main body to the paper cassette via this terminal.

After the paper stacking operation is completed and the paper feed cassette is inserted into the main body, the light emitted by the light emitting element such as an LED installed on the main body is reflected by the reflector attached to the paper height detecting unit. Then, the remaining amount of paper is detected by monitoring it with a light receiving element installed in the main body. The reflector is mounted at an angle, not perpendicular to the light source. By doing so, the projection position of the reflected light on the main body can be changed according to the height of the paper surface, and this can be used to detect the height of the paper surface. A plurality of light receiving elements used for detection are prepared and installed so as to cover the projection position on the main body which changes depending on the height of the paper surface, so that the remaining amount of paper can be sequentially detected. The detection results are sequentially displayed on the display unit of the main body.

In this way, the paper height detecting sensor unit which can move up and down is attached to the rear end regulating plate of the paper feeding cassette.
By attaching a terminal there, the upper limit of paper loading can be detected. The light from the main body light source is reflected by the reflection plate of the sensor unit, so that the remaining amount of paper can be sequentially detected.

[0041]

As described above, according to the first aspect of the present invention, when loading paper in a state where the paper feed cassette is pulled out of the printer main body partway, the paper cassette is installed in the printer main body or the paper feed cassette. The upper and lower movable or angle-changeable arms detect the height of the paper at the time of paper loading, thereby enabling the upper limit of the paper loading to be detected and the remaining amount of paper to be sequentially detected.

According to the second aspect of the present invention, a portion having a curvature is further provided at the tip of the arm to reduce the rubbing resistance of the paper conveyance, thereby using the arm as an auxiliary member for the paper conveyance. Enabled.

According to the third aspect of the present invention, the transmitting unit is installed on the paper cassette side and the receiving unit is installed on the printer main body, so that the paper cassette is pulled out of the printer main body halfway. When stacking paper in a state where the paper cassette is completely removed from the main body, the result of the paper stack upper limit detection can be disclosed to the user by the printer main body.

[Brief description of the drawings]

FIG. 1 is a sectional view of a printer main body according to a first embodiment (when a paper feed cassette is inserted).

FIG. 2 is an enlarged view of a sheet feeding cassette unit according to the first embodiment.

FIG. 3 is a cross-sectional view of the printer main body according to the first embodiment (a state in which a sheet feeding cassette is half removed).

FIG. 4 is an enlarged view of a sheet height detection sensor unit according to the first embodiment.

FIG. 5 is a cross-sectional view of the printer main body according to the second embodiment (at the time of paper stacking operation).

FIG. 6 is an enlarged view of a cassette lock release button in the second embodiment.

FIG. 7 is an explanatory view of the movement of the elliptical member in the third embodiment.

FIG. 8 is a view of a sheet cassette according to a fourth embodiment as viewed from above.

FIG. 9 is a sectional view of a sheet feeding cassette according to a fourth embodiment.

FIG. 10 is a side view of a sheet feed cassette according to a fourth embodiment.

FIG. 11 is a paper height detection sensor unit according to a fifth embodiment.

FIG. 12 is a sectional view of a sheet cassette according to a fifth embodiment.

FIG. 13 is an enlarged view of an angle detection sensor according to a fifth embodiment.

FIG. 14 is a sectional view of a printer main body according to a sixth embodiment.

FIG. 15 is a sectional view of a sheet feeding cassette according to a sixth embodiment.

FIG. 16 is a configuration diagram in a conventional example.

[Symbol of sign]

 DESCRIPTION OF SYMBOLS 11 Printer main body 12 Paper feed cassette 13 Paper 14a Paper feed roller 14b Main body relay roller 15 Paper height detecting sensor 16 Paper transport path 17 Rear end regulating plate 18a-d Hole for paper height detecting photo sensor 18e Loading upper limit detecting photo sensor Hole 19 Photosensor 21 Lock release button 31 Conveyor roller 41 Paper height indicator 42 Spring 51 Angle detection sensor 61a Light emitting element 61b Light receiving element 62 Reflector 63 Reflector 63 Paper height detection terminal 64 Radio transmission unit 65 Radio reception unit 101 Paper loading upper limit display seal 102 Paper loading upper limit display stamp

Claims (3)

[Claims] 1. A printer having a paper feed cassette, wherein the positional relationship between the paper feed cassette and the printer main body is 1, a state where the paper cassette is completely inserted, a state where the printer is partially pulled out, and a state where the paper cassette is completely pulled out. It has three states, has an arm-shaped member that can move up and down or can change its posture, has a device for detecting a change in the arm-shaped member, and has means for disclosing detected information to a user. Then, in the state 2 or 3 of the above three states, the arm-shaped member abuts on the paper surface stored in the cassette, and the position or posture of the arm-shaped member is changed according to the paper load amount and the presence or absence of paper. A paper height detecting device characterized by detecting a change and detecting it by a detecting device and disclosing it to a user. 2. The paper height detecting device according to claim 1, wherein the arm-shaped member has a freely rotatable member at a tip thereof and is used as a transport roller using the member. 3. A sheet cassette has an arm-shaped member which can move up and down or can change its posture, and the sheet cassette has a device for detecting a change in the arm-shaped member. The paper feed cassette has a transmitting device for transmitting information, the printer has a device for receiving the transmitted information, and the printer has means for disclosing the information to a user. 2 out of 3 states
Alternatively, in the state of 3, the arm-shaped member comes into contact with the paper surface accommodated in the cassette, and the position or posture of the arm-shaped member changes according to the amount of loaded paper and the presence / absence of paper, which is detected by the detecting device. 2. The paper height detecting device according to claim 1, wherein the information is transmitted by a transmitting device installed in a paper cassette, and the information is received by a receiving device of the printer body and disclosed to a user.