JP6003202B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a printer, and more particularly to an image forming apparatus that can be used by changing an installation posture.

In general, an image forming apparatus such as a printer is used in a posture (horizontal posture) in which a sheet placement surface of a paper feed tray is in a substantially horizontal state. This is because the recording sheets stacked on the paper feed tray can be fed smoothly without bending.
However, for example, when used in a general home, there is not much room for installation, so it is convenient if the image forming apparatus can be used in a vertical position.

  Therefore, in recent years, an image forming apparatus that can be used either horizontally or vertically according to the installation space has been proposed (for example, Patent Document 1).

JP-A-8-314333

However, in the conventional image forming apparatus, when the sheet is placed horizontally, the sheet placing surface of the sheet feeding tray is in a substantially horizontal state. The surface becomes almost vertical, and the recording sheet cannot be placed.
Therefore, a method is considered in which the paper feed tray is configured to be detachable in the image forming apparatus, and the user can change the mounting position of the paper feed tray as the user changes the installation posture of the image forming apparatus. Since a complicated operation is forced, the problem that user friendliness falls may arise.

  The present invention has been made in view of the above-described problems, and in an image forming apparatus in which the installation posture can be changed, even if the installation posture is changed, the recording sheet is not forced to a complicated operation. An object of the present invention is to provide an image forming apparatus capable of placing the image on the paper feed tray.

In order to achieve the above object, an image forming apparatus according to the present invention is capable of forming an image regardless of whether the apparatus is installed in a horizontal position or in a vertical position. a is a paper feed tray in which the recording sheet is subjected to image formation are stacked, according to the installation position of the device, as the mounting surface of the recording sheet in the paper feed tray faces the upper side in the lead direction perpendicular Switching means for automatically switching the posture of the paper feed tray with respect to the apparatus main body, the paper feed tray is pivotally supported by the apparatus main body, and the switching means has a horizontal posture. When the posture of the paper feed tray is sometimes maintained in the first posture and is set in the vertical posture, the switching means is configured to swing and switch to a second posture that opens outward from the first posture. Change from the first position to the second position An urging means for urging the paper feed tray in a direction, and in a horizontal position, the urging means abuts against a horizontal surface on which the apparatus is installed, and the urging force is applied to the paper feed tray by the urging means. An abutting member that maintains the first posture against the above, and when the apparatus is changed from the horizontal posture to the vertical posture, the abutting state between the abutting member and the installation surface is released. Then, the feeding tray is swung to the second posture and switched by the biasing force of the biasing means .

  And a pickup roller for coming into contact with an upper surface of the uppermost recording sheet stacked on the sheet feeding tray and feeding the recording sheet from the sheet feeding tray, the pickup roller being integrated with the sheet feeding tray. It is desirable to be configured so as to swing.

  According to the above configuration, the sheet feeding with respect to the apparatus main body is performed by the switching unit so that the recording sheet placement surface in the paper feed tray faces the upper side in the vertical direction in both the horizontal posture and the vertical posture. Since the posture of the tray can be switched, the recording sheet can be placed on the paper feed tray without forcing the user to perform complicated operations, and user friendliness can be improved.

It is a schematic sectional drawing which shows the state installed in the horizontal attitude | position of the printer which concerns on 1st Embodiment. (A) And (b) is an operation | movement figure in the case of folding the paper feed tray of the said printer. It is a schematic sectional drawing which shows the state which installed the said printer in the vertical installation attitude | position. It is a schematic sectional drawing which shows the state which installed the printer which concerns on 2nd Embodiment in a horizontal position. It is a schematic sectional drawing which shows the state which installed the printer which concerns on 2nd Embodiment in the vertical installation attitude | position. It is a schematic sectional drawing which shows the state which installed the printer which concerns on 3rd Embodiment in the horizontal position. It is a schematic sectional drawing which shows the state which installed the printer which concerns on 3rd Embodiment in the vertical installation attitude | position. It is a block diagram which shows the control part of the printer which concerns on 3rd Embodiment, and its control object. It is a flowchart which shows the execution procedure of the paper feed tray attitude | position control performed in the said control part.

An embodiment of an image forming apparatus according to the present invention will be described using a printer that forms an image by an electrophotographic method as an example.
(1) First Embodiment Hereinafter, an image forming apparatus according to a first embodiment of the present invention will be described with reference to the drawings.

(1-1) Configuration of Image Forming Apparatus FIG. 1 is a schematic cross-sectional view for explaining the configuration of a monochrome printer that is an example of an image forming apparatus according to the first embodiment of the present invention.
The printer 1 has a rectangular parallelepiped casing 2, and a posture (hereinafter referred to as “horizontal posture”) in which the sheet feeding tray 21 is installed in a state of being almost horizontal with the surface 2 a of the casing 2 facing downward. ) And a posture (hereinafter, referred to as a “vertical posture”) that is installed with the surface 2b orthogonal to the surface 2a and having a smaller area than the surface 2a facing downward. FIG. 1 shows a state of the horizontal posture.

That is, the user can normally select the horizontal orientation as the installation posture of the printer 1, and can select the vertical orientation when the installation space is limited.
The printer 1 has a cylindrical photosensitive drum 12 that is rotationally driven in a direction indicated by an arrow A.
Around the photosensitive drum 12, a charger 14, an optical unit 15, a developing device 16, and a transfer roller 17 for forming a toner image on a recording sheet by an electrophotographic method are arranged in the rotational direction of the photosensitive drum 12 ( They are arranged in this order along the counterclockwise direction in FIG.

In the printer 1, the control unit 50 converts image data input from an external device into a laser diode drive signal, and the laser diode provided in the optical unit 15 is driven by the drive signal.
As a result, the laser beam LB corresponding to the image data is emitted from the optical unit 15 to the surface of the photosensitive drum 12.

The surface of the photosensitive drum 12 is charged to a predetermined potential by the charger 14 in advance, and is exposed to the laser beam LB emitted from the optical unit 15, so that the electrostatic latent image is formed on the surface of the photosensitive drum 12. An image is formed. The electrostatic latent image is developed with toner in the developing device 16 to form a toner image.
A sheet feeding unit 20 is provided below the photosensitive drum 12. The paper feed unit 20 includes a paper feed tray 21 and a pickup roller 25 that accommodate a plurality of recording sheets S such as paper and OHP sheets in a stacked state.

Here, as shown in FIG. 1, the paper feed tray 21 includes a tray body 22, a main tray 23, an extension tray 24, and the like.
The tray body 22 has a lifting plate 22b that swings in the direction of arrow B (vertical direction) about the support shaft 22a and a frame 22d by a cam mechanism (not shown).
Here, the frame 22d is pivotally supported by the housing 2 via the support shaft 21a, so that the paper feed tray 21 is swingable.

The recording sheet S for image formation is placed at a position indicated by a two-dot chain line on the paper feed tray 21 as shown in FIG.
When the elevating plate 22b is raised and the leading edge of the recording sheet S is lifted, the uppermost recording sheet on the sheet feeding tray 21 is fed out to contact the rotating pickup roller 25 and is applied to the photosensitive drum 12. To the transport path 26.

At this time, even if the second and subsequent recording sheets S are carried along, the sheet-shaped separating pad 29 is provided at a position in contact with the pickup roller 25 on the transport path 26, so the second and subsequent recording sheets S are provided. The recording sheet S is prevented from being fed by the separation pad 29, and the occurrence of double feeding is suppressed.
A transfer roller 17 that rotates in the direction of arrow C is disposed in pressure contact with the peripheral surface of the photosensitive drum 12, thereby forming a transfer nip 27. The recording sheet S that has passed through the conveyance path 26 is conveyed into the transfer nip 27.

While the recording sheet S passes through the transfer nip 27, the toner image carried on the photosensitive drum 12 is transferred onto the recording sheet S by the action of the transfer electric field generated by the transfer voltage applied to the transfer roller 17. The
The surface of the photosensitive drum 12 after the toner image is transferred to the recording sheet S is cleaned by a cleaning blade (not shown) or the like.

On the other hand, the recording sheet S to which the toner image is transferred is conveyed to the fixing unit 30.
The fixing unit 30 includes a fixing roller 31 and a pressure roller 32 arranged in parallel, and a fixing nip is formed between the fixing roller 31 and the pressure roller 32.
The fixing roller 31 has a built-in halogen heater 33, which heats the fixing roller 31.

The recording sheet S that has passed through the fixing nip is conveyed to the paper discharge roller 40 by the fixing roller 31 and the pressure roller 32, and is discharged onto the paper discharge tray 41 by the paper discharge roller 40.
A detachable extension tray 41a is mounted on the downstream side of the sheet discharge tray 41 so that the leading end does not hang down even when the recording sheet S is large.

(1-2) Configuration of Paper Feed Tray In the printer 1 according to the first embodiment, the paper feed tray 21 swings and the inclination with respect to the housing 2 is changed according to the installation posture. .
Hereinafter, the configuration of the paper feed tray 21 will be described.
As shown in FIG. 1, the paper feed tray 21 includes a tray body 22, a main tray 23, an extension tray 24, and the like as described above.

The main tray 23 has a plurality of ribs 23 b provided on the upper surface thereof in parallel with each other along the conveyance direction of the recording sheet S.
As shown in FIG. 1, the surface on which the recording sheet S is placed in the paper feed tray 21 is composed of the upper surface 22 c of the elevating plate 22 b of the tray body 22, the upper edge portions 23 c of the plurality of ribs 23 b, and the upper surface 24 b of the extension tray 24. It consists of and.

Here, the above-mentioned whirling pad 29, the pickup roller 25, and a driving source (not shown) for driving the rotation are provided on the frame 22d.
The extension tray 24 is connected to the main tray 23, and the main tray 23 is connected to the tray main body 22 via support shafts 24a and 23a, respectively.
The printer 1 is provided with a regulating member 11 that regulates the swing range of the paper feed tray 21. The restricting member 11 will be described later.

On the upper surface of the elevating plate 22b of the tray main body 22, a pair of guide plates 22e are provided on both sides in the depth direction of FIG.
The recording sheet S for image formation is guided by the pair of guide plates 22e at both ends in the width direction (direction perpendicular to the transport direction) and in the transport direction.

When the small-size recording sheet S is placed on the paper feed tray 21, as shown in FIG. 2A, the extension tray 24 is swung in the direction of arrow D about the support shaft 24a. Further, it can be moved from the position P1 of the two-dot chain line to the position P2 of the solid line and can be stacked on the main tray 23, so that the installation space can be saved.
In that case, the surface on which the recording sheet S is placed in the paper feed tray 21 is the upper surface 22c of the elevating plate 22b of the tray body 22 and the back surface 24c of the extension tray 24 opposite to the upper surface 24b.

Further, when the printer 1 is not used or transported, the main tray 23 and the extension are extended as shown in FIG. 2B by swinging the main tray 23 in the direction of arrow E about the support shaft 23a. The tray 24 can be stored in the housing 2.
Thereby, the storage space of the printer 1 can be further saved.
2A and 2B, the regulating member 11 is not shown in order to make the drawing easier to see.

FIG. 3 is a diagram illustrating a state in which the printer 1 is installed in a vertical posture.
A torsion coil spring 28 is externally attached to a support shaft 21a that supports the frame 22d.
One end of the torsion coil spring 28 is fixed to the frame 22 d, and the other end is fixed by a fixing member 2 c provided on the housing 2.
The torsion coil spring 28 is set so that its restoring force acts in a direction in which the frame 22d swings counterclockwise with respect to the housing 2 around the support shaft 21a in FIG.

  In the case of the horizontal orientation, as shown in FIG. 1, the projection 22 f of the frame 22 d abuts on the installation surface G on which the apparatus is installed and pushes up the paper feed tray 21. A force against the restoring force 28 (hereinafter, simply referred to as “drag”) is generated, and the frame 22 d moves backward to a position where it is hidden inside the housing 2. At this time, the paper feed tray 21 is in a substantially horizontal state, and the recording sheet S can be placed thereon.

On the other hand, in the case of the vertically placed posture, as shown in FIG. 3, the projection 22f of the frame 22d does not abut on the installation surface G, and the drag does not occur. Oscillates counterclockwise about the support shaft 21a.
Further, as described above, the regulating member 11 that regulates the swing range of the paper feed tray 21 is provided between the tray body 22 and the housing 2.

The restricting member 11 is configured such that the ends of the two arm portions 11a and 11b are swingably connected to each other by the support shaft 11c, and the end portions of the arm portions 11a and 11b on the side where the connection is not performed. These are pivotally supported on the inner side surface of the housing 2 and the side surface of the tray main body 22 by pivots 11d and 11e, respectively.
That is, as shown in FIG. 1, the arm portions 11a and 11b are further expanded from the state of the "<" character as shown in FIG. 11d and 11e are in a state of being in a straight line, the edge of the arm portion 11a abuts on the bent portion 11f of which the edge is bent at a right angle in the arm portion 11b. The swinging motion that swings so that the paper feed tray 21 opens outwardly from the surface 2a of the housing 2 is stopped because it cannot swing clockwise.

As a result, even when the sheet feeding tray 21 is placed in the vertical orientation, the recording sheet S can be placed so as to lean against it because it faces slightly upward in the vertical direction.
Note that, as described above, the regulating member 11 is placed in the vertical orientation because the opening operation of the “<” character is stopped just before the support shafts 11 c, 11 d, and 11 e are in a straight line. When the sheet feeding tray 21 is pushed upward as the posture is changed from the horizontal position, the arm portions 11a and 11b naturally bend and the sheet feeding tray 21 approaches the surface 2a of the housing 2. Can be swung in the direction.

In addition, when the user installs the printer 1 in the vertical orientation, the user removes the extension tray 41a (see FIG. 1) provided to extend the placement surface of the discharge tray 41, as shown in FIG. Another extension tray 42 is attached to the housing 2.
As a result, a slightly upward placement surface that is slightly inclined from the vertical direction is formed, so that the discharged recording sheets S can be stacked. In addition, if the extension tray 41a is designed to have a shape that can be used even when placed vertically, it is not necessary to provide the extension tray 42 separately, and the cost of equipment can be reduced.

As described above, in the first embodiment, the torsion coil spring 28 urges the paper feed tray 21 in the direction to open the outside of the housing 2. The paper tray 21 is opened to the outside, and the opening angle is restricted to a predetermined range by the restriction member 11 so that the posture of the paper feed tray 21 is maintained.
In the horizontal orientation, the installation surface G naturally abuts against the protrusion 22f and pushes up the paper feed tray 21 against the urging force, so that the frame 22d is hidden inside the housing 2. Retreat until. Thereby, the paper feed tray 21 is kept substantially horizontal.

Thus, as the user changes the installation posture of the printer 1, the posture of the paper feed tray 21 is naturally changed so that the recording sheet placement surface faces upward in the vertical direction. However, user-friendliness can be improved without being forced to perform complicated operations.
(2) Second Embodiment (2-1) Configuration of Image Forming Apparatus Hereinafter, a printer that is an example of an image forming apparatus according to a second embodiment of the present invention will be described with reference to the drawings.

The configuration of the printer according to the second embodiment is basically the same as that of the printer 1 according to the first embodiment. However, in the printer 100 according to the second embodiment, instead of the torsion coil spring 28, a horizontal The printer 1 is different from the printer 1 in that a swing mechanism 120 for swinging the frame 22d when the posture is changed from the vertical position to the vertical position is provided.
In the following, common constituent parts will be denoted by the same reference numerals as those in the first embodiment, description thereof will be omitted, and differences will be mainly described.

FIG. 4A is a partial schematic cross-sectional view showing the configuration of the printer 100 according to the second embodiment, and FIG. 4B is a partial cross-sectional view thereof.
FIG. 4A shows a state where the printer 100 is installed in the horizontal orientation, and the side surface portion on the front side of the paper surface in the housing 2 is omitted.
The swing mechanism 120 includes the above-described frame 22d, rods 121 and 122, stepped bolts 123a to 123e, and the like.

The rod 121 has a plate shape and is provided with elongated holes 121a and 121b along the longitudinal direction. Stepped bolts 123a and 123b are respectively inserted into these rods 121 and inside the casing 2 (not shown). ) Is supported so as to be slidable in the left-right direction on the paper surface.
The rod 121 is configured such that an end 121d protrudes outward from a through hole 2d provided in the surface 2b of the housing 2.

FIG. 4B is a partial cross-sectional view taken along the line FF ′ in FIG. 4A, and shows an engaged state between the long hole 121 a and the stepped bolt 123 a in the rod 121.
In addition, the stepped bolt 123b and stepped bolts 123c to 123e described later have the same structure as the stepped bolt 123a.
The rod 122 has a plate shape and is provided with an elongated hole 122a along the longitudinal direction. Stepped bolts 123c and 123d are inserted into the rod 122 and screwed into the inside of the housing 2 (not shown). By doing so, it is slidably supported in the vertical direction.

Further, as shown in FIG. 4A, an elongated hole 122b is provided at the end of the rod 122 along a direction orthogonal to the longitudinal direction.
The stepped bolt 123e is screwed into the frame 22d while being inserted into the elongated hole 122b.
Furthermore, the rod 121 and the rod 122 each have an inclined surface 121c and an inclined surface 122d inclined at an angle θ1 [°] and an angle θ2 [°] with respect to a horizontal plane, respectively. They are configured to slidably contact each other.

Here, both θ1 [°] and θ2 [°] are set to be approximately 45 [°].
The inclined surfaces 121c and 122d are made of a material having a high slidability, such as a low-friction sheet attached to the surface, or the rod 121 and the rod 122 itself so that the frictional force when they are in sliding contact with each other is reduced. It is desirable to use it.

  In such a configuration, when the printer 100 is in the horizontal orientation, the projection 22f of the frame 22d abuts the installation surface G and the paper feed tray 21 as in the printer 1 of the first embodiment. Is pushed upward and the frame 22d is retracted to a position hidden inside the housing 2, so that the paper feed tray 21 is in a substantially horizontal state, and the recording sheet S can be placed thereon.

On the other hand, when the printer 100 is changed from the horizontal position to the vertical position, as shown in FIG. 5, the end 121d of the rod 121 abuts the installation surface G, and the rod 121 moves in the arrow J direction. Pushed up.
Accordingly, the inclined surface 121d of the rod 122 tends to be pushed upward by the inclined surface 121c, but only movement in the horizontal direction is allowed, and the force from the inclined surface 121c to the left side of the paper surface Move in the K direction.

Eventually, the stepped bolt 123c inserted into the elongated hole 122a of the rod 122 comes into contact with the end of the elongated hole 122a, and the movement stops.
With this moving operation, the frame 22d engaged with the rod 122 via the stepped bolt 123e swings in the L direction around the support shaft 21a, and the paper feed tray 21 is opened to the outside of the housing 2. become.

As a result, the placement surface (upper surface 22c, upper edge portion 23c, upper surface 24b) of the paper feed tray 21 faces slightly upward in the vertical direction, so that the recording sheet S can be placed in a leaning manner.
In this way, the rod 121 and the rod 122 and the stepped bolts 123a to 123e that slidably support them convert the operation of the rod 121 entering the housing 2 into the swing operation of the paper feed tray 21. Functions as an operation direction conversion mechanism.

As described above, in the second embodiment, as the user changes the installation posture of the printer 100, the paper feed tray 21 is oriented so that the recording sheet placement surface faces upward in the vertical direction. Since it is changed naturally, the user is not forced to perform complicated operations, and user friendliness can be improved.
(3) Third Embodiment (3-1) Configuration of Image Forming Apparatus Hereinafter, a printer that is an example of an image forming apparatus according to a third embodiment of the present invention will be described with reference to the drawings.

  The configuration of the printer 200 according to the third embodiment is basically the same as that of the printer 100 according to the second embodiment. However, in the printer 200 according to the third embodiment, the operation direction conversion mechanism is replaced. In addition, a swing drive mechanism 220 that swings and drives the paper feed tray 21 when the posture is changed is provided, and a posture detection unit 51 that detects the posture of the printer 200 is provided. The control unit 50 is different from the printer 100 in that the detection result of the posture detection unit 51 is acquired and the posture of the paper feed tray 21 is controlled.

In the following, common constituent parts are denoted by the same reference numerals as those in the second embodiment, description thereof will be omitted, and differences will be mainly described.
FIG. 6 is a partial schematic cross-sectional view illustrating a configuration in which the printer 200 according to the third embodiment is installed in the horizontal orientation, and FIG. 7 is a state in which the printer 200 is installed in the vertical orientation. FIG.

As shown in FIG. 6, the posture detection unit 51 is a push switch having an actuator 51 a that protrudes outward from the surface 2 b of the housing 2, and when the installation posture is set vertically, as shown in FIG. 7, When the actuator 51a is pushed up in contact with the installation surface G, a signal indicating that the posture is currently in the vertical position is output to the control unit 50.
As shown in the figure, the swing drive mechanism 220 includes a paper feed tray drive unit 230, a screw gear 230a provided at the tip of the rotation shaft thereof, a helical gear 222e provided on the frame 222d, and the like. Consists of. Here, the screw gear 230 a and the helical gear 222 e form a worm gear 231.

And when it sees from the axial direction of the support shaft 21a, it is comprised so that the position of the shaft center of the said support shaft 21a and the shaft center of the helical gear 222e may correspond.
The paper feed tray drive unit 230 is a motor capable of controlling the amount of rotation, such as a stepping motor.
In the configuration described above, in the printer 200 according to the third embodiment, when the paper feed tray driving unit 230 is driven, the driving force is transmitted from the screw gear 230a to the helical gear 222e, and the frame 222d is It is configured to swing about the support shaft 21a.

(3-2) Configuration of Control Unit FIG. 8 is a diagram illustrating the relationship between the configuration of the control unit 50 in the printer 200 and the main components that are the control targets.
As shown in the figure, the control unit 50 receives a signal output from the posture detection unit 51 and performs input / output of signals among the image processing unit 10, the paper feeding unit 20, and the fixing unit 30. Control these.

Here, the image processing unit 10 is a unit in which the charger 14, the optical unit 15, the developing unit 16, the transfer roller 17, the photosensitive drum 12, and their drive sources (not shown) are collected.
The control unit 50 includes a CPU 150, a communication interface (I / F) unit 151, a RAM 152, a ROM 153, and an EEPROM 154 as main components.
The communication I / F unit 151 is an interface for connecting to a LAN such as a LAN card or a LAN board.

A RAM (Random Access Memory) 152 is a volatile memory and serves as a work area when the CPU 150 executes a program.
A ROM (Read Only Memory) 153 stores a control program for performing control related to execution of printing.
An EEPROM (Electronically Erasable and Programmable Read Only Memory) 154 is a nonvolatile memory and serves as a data storage area of the CPU 150.

The stored data includes information indicating the relative attitude of the paper feed tray 21 with respect to the housing 2 at the present time (hereinafter referred to as “tray attitude information”).
Here, the tray posture information is a posture in which the tray main body 22 of the paper feed tray 21 is accommodated inside the surface 2a of the housing 2 as shown in FIG. 6 (hereinafter referred to as “first posture”). As shown in FIG. 7, the flag indicates which of the postures (hereinafter referred to as “second posture”) that opens outward from the surface 2 a of the housing 2.

A CPU (Central Processing Unit) 150 executes warm-up, print execution, and the like by executing a control program stored in the ROM 153.
Further, the CPU 150 changes the relative angle of the paper feed tray 21 with respect to the housing 2 so that the placement surface of the paper feed tray 21 faces upward in the vertical direction when the installation posture is changed. As shown in FIG.

(3-3) Content of Paper Tray Posture Control Hereinafter, paper feed tray posture control executed by the control unit 50 according to the third embodiment will be described with reference to the flowchart of FIG.
When the main power is turned on, the CPU 150 starts paper feed tray attitude control.
First, the CPU 150 acquires a detection result from the attitude detection unit 51 (step S11), and acquires tray attitude information stored in the EEPROM 154 (step S12).

And it is determined from the detection result of the attitude | position detection part 51 whether the present installation attitude | position is vertical (step S13).
If it is not vertically placed, it is determined whether or not the paper feed tray 21 is in the first posture, and if the posture indicated by the tray posture information is in the first posture (step S14: YES). It is determined whether or not an instruction to turn off the power is accepted (step S17).

  Here, when an instruction to turn off the power is received (step S17: YES), if the paper feed tray 21 is not in the first posture, the paper feed tray driving unit 230 is driven to rotate to feed the paper feed tray 21. Is changed to the first posture, and the content of the tray posture information is rewritten to the first posture (step S18), the main paper feed tray posture control is terminated, and the paper feed tray 21 assumes the first posture. If so, the paper feed tray attitude control is immediately terminated.

It should be noted that when a predetermined drive pulse is output to the paper feed tray driving unit 230 and the paper feed tray 21 is swung to the first posture, a stopper (not shown) just protrudes from the inner surface of the housing 2. ) Is in contact with the tray main body 22 and its position is regulated.
As described above, the reason why the sheet feeding tray 21 is accommodated inside the surface 2a of the housing 2 before the power is turned off is as follows.

  That is, even when the user changes the installation position of the printer 200 from the vertical position to the horizontal position when the power is turned off, if the paper feed tray 21 is always in the first position when the power is turned off, Since the tray body 22 of the paper tray 21 is accommodated in the housing 2, it is difficult to apply a large external force to the tray body 22, and even if an external force is applied, this external force is applied to a stopper (not shown). This is because an external force does not reach the swing drive mechanism 220, and damage or failure of the swing drive mechanism 220 can be prevented.

On the other hand, if an instruction to turn off the power is not accepted in step S17, the processing from step S11 to step S17 is repeatedly executed.
The transition from step S17 to step S11 is executed after a time of, for example, 3 [sec] in order to avoid an increase in the load on the CPU 150.
In step S14, when the posture indicated by the tray posture information is not the first posture, the CPU 150 rotates the paper feed tray driving unit 230 to bring the paper feed tray 21 into the first posture. The content is changed (step S15), the contents of the tray posture information stored in the EEPROM 154 are rewritten to the first posture (step S16), and the process proceeds to step S17 to determine whether or not the power-off instruction is accepted. To do.

Further, when it is determined in step S13 that the posture is vertical (step S13: YES), it is determined whether the frame 22d of the paper feed tray 21 is in the first posture, and the first posture is determined. If not (step S19: NO), the process proceeds to step S17 for determining whether or not the above-mentioned power-off instruction is accepted.
If it is in the first posture (step S19: YES), the CPU 150 rotates the paper feed tray drive unit 230 to change the paper feed tray 21 to the second posture (step S20). The content of the tray posture information stored in the EEPROM 154 is rewritten to the second posture (step S21), and step S17 and subsequent steps for determining whether or not the above-mentioned power-off instruction is accepted are performed.

In the third embodiment, the power is not turned off until a predetermined time elapses after the power-off instruction is received.
The predetermined time is set to a time sufficient to change the paper feed tray 21 from the first posture to the second posture.
As described above, in the third embodiment, when the installation posture of the printer 200 is changed, the control unit 50 acquires the current installation posture of the printer 200 via the posture detection unit 51, and the installation posture. Accordingly, the feed tray drive unit 230 is rotated to change the posture of the feed tray 21 so that the recording sheet placement surface of the feed tray 21 faces upward in the vertical direction.

In step S13, it is determined whether or not the current installation posture is not in the vertical orientation. The state in which the current installation posture is not in the vertical orientation here is not only in the horizontal orientation state but also between the horizontal orientation and the vertical orientation. This includes the middle of state changes.
If, in step S13, when it is determined whether the horizontal position, as soon as no longer horizontal posture by tilting the housing 2 slightly, in step S 20 described above, the posture of the paper feed tray 21 is first The posture is changed from the first posture to the second posture.

Then, the paper feed tray 21 to be opened to the outside of the housing 2 comes into contact with the installation surface G and is damaged, or an excessive load is applied to the paper feed tray driving unit 230 that swings the paper feed tray 21. May shorten the service life.
In order to avoid such a problem, it is desirable to maintain the paper feed tray 21 in the first posture until the vertical posture is confirmed.

Under such circumstances, in step S13, it is determined whether or not the current installation posture is vertical.
As described above, in the third embodiment, as the user changes the installation posture of the printer 200, the posture of the paper feed tray 21 is set so that the placement surface of the paper feed tray 21 faces upward in the vertical direction. Therefore, since the user can place the recording sheet S on the paper feed tray 21 without performing a complicated operation, user friendliness can be improved.
<Modification>
The present invention is not limited to the above-described embodiment, and the following modifications may be implemented.

(1) In the first embodiment, the torsion coil spring 28 is used to bias the paper feed tray 21 to open outward from the surface 2a of the housing 2, but the paper feed tray 21 is biased. The biasing means to be performed is not limited to this, and may be a compression spring or an elastic member such as rubber.
(2) In the second embodiment, the values of the angles θ1 [°] and θ2 [°] of the inclined surfaces at the engaging portions of the rod 121 and the rod 122 are both approximately 45 [°]. Not limited.

It is desirable that the values of θ1 [°] and θ2 [°] are basically set to the same value, and the specific angle is determined by the rod 122 swinging the paper feed tray 21 as the rod 121 moves. Any angle can be used as long as it is movable in the direction of movement.
(3) In the third embodiment, the tray posture information is a flag indicating which one of the first posture and the second posture, but the present invention is not limited to this.

For example, the relative posture of the paper feed tray 21 with respect to the housing 2 can be recognized as follows.
The control unit 50 outputs drive pulses to the paper feed tray drive unit 230 in order to rotate it forward and backward, and the rotation amount (angle) per drive pulse is determined.
Here, the control unit 50 sets the initial value every time when a drive pulse is output once for the forward rotation drive, with reference to the time when the paper feed tray 21 is in the first posture (see FIG. 6). The count value to 0 is incremented by 1 and every time a drive pulse is output for reverse rotation driving, the count value is decremented by 1 and updated each time the count value is updated. It is assumed that the counted value is stored in the EEPROM 154.

Since the count value indicates the inclination angle of the paper feed tray 21 based on the first posture, such a count value may be stored in the EEPROM 154 as tray posture information.
In this way, even if a power failure occurs and the power supply is suddenly cut off, the CPU 150 obtains the count value from the EEPROM 154 at the time of power recovery, so that the current supply can be promptly performed. The inclination angle of the paper tray 21 can be grasped, and the paper feed tray attitude control can be executed more reliably.

(4) In the third embodiment, the posture detection unit 51 is used as the acquisition unit that acquires the installation posture of the printer 200. However, the present invention is not limited to this.
For example, an operation panel (not shown) of the printer 200 or other appropriate manual switch may be used as an accepting unit, and designation of an installation posture may be accepted from a user. In addition, the installation posture of the printer may be detected by detecting the direction in which the gravitational acceleration acts using an inclination sensor or an acceleration sensor.

(5) Although the above embodiment shows an example in which the image forming apparatus according to the present invention is applied to a printer, the present invention can be applied not only to a printer but also to a facsimile machine or a multifunction machine having these functions. is there.
(6) In the above embodiment, an image forming apparatus (printer) that forms an image by an electrophotographic method has been described as an example. However, the image forming apparatus according to the present invention is not limited to an electrophotographic method, for example, an inkjet. The present invention can also be applied to a type image forming apparatus.

  The present invention can be widely applied to an image forming apparatus that can change the installation posture and includes a paper feed tray on which recording sheets used for image formation are stacked.

DESCRIPTION OF SYMBOLS 1,100,200 Printer 2 Housing | casing 2a, 2b, 22c, 24b, 24c Surface 2d Through-hole 17 Transfer roller 20 Paper feed part 21 Paper feed tray 22 Tray main body 22b Lifting plate 22d Frame 22e Guide plate 22f Protrusion part 23 Main tray 23a, 24a Support shaft 24 Extension tray 29 Separation pad 50 Control unit 51 Attitude detection unit 120 Oscillation mechanism 121, 122 Rod 121a, 122a, 122b Long hole 121c, 122d Inclined surface 123a-123e Stepped bolt 220 Oscillation drive mechanism 222d Frame 222e Helical gear 230 Paper feed tray driver 230a Screw gear

Claims (2)

An image forming apparatus capable of forming an image in either case where the apparatus is installed in a horizontal position or in a vertical position,
A paper feed tray on which recording sheets for image formation are stacked;
According to the installation attitude of the apparatus, so as to face the upper side mounting surface of the recording sheet in the paper feed tray is in the lead straight direction, and a switching means for automatically switching the position of the paper feed tray to the apparatus main body ,
The paper feed tray is pivotally supported by the apparatus main body so as to be swingable.
The switching means is
Keep the feed tray in the first position when in the horizontal position,
When it is in a vertical position, it is configured to swing and switch to a second position that opens outward from the first position,
The switching means is
Biasing means for biasing the paper feed tray in a direction to change from the first posture to the second posture;
An abutting member that abuts against a horizontal installation surface on which the apparatus is installed in a horizontal posture, and maintains the paper feed tray in a first posture against the urging force of the urging means;
Have
When the apparatus is changed from the horizontal position to the vertical position, the contact state between the contact member and the installation surface is released, and the paper feed tray is moved to the second position by the biasing force of the biasing means. An image forming apparatus characterized by being switched by swinging . A pickup roller that abuts on the upper surface of the uppermost recording sheet stacked on the sheet feeding tray and feeds the recording sheet from the sheet feeding tray;
The image forming apparatus according to claim 1 , wherein the pickup roller is configured to swing integrally with the paper feed tray.

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