JP2001253090A - Apparatus for detecting residual quantity of ink in ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for detecting the residual quantity of ink in an ink jet printer in which the detection accuracy can be enhanced by increasing the tolerance of the incident angle of light to the interface at a prism part and the tolerance of distance to the prism part. SOLUTION: A prism part 61 is provided on the bottom face of each ink tank 15a-15d and the prism part 61 is provided with a first inclination interface 61a for refracting incident light from a light emitting element 62 located on the outside of a recording sheet in the widthwise direction thereof, a second inclination interface 61b for reflecting or refracting the incident light refracted on the first inclination interface, a third inclination interface 61c for reflecting or refracting the light reflected on the second inclination interface, and a fourth inclination interface 61d for refracting the light reflected on the third inclination interface to be in parallel with the incident light from the light emitting element. Angle of the first inclination interface is set such that the incident angle of light to the second inclination interface is altered to 52 deg. which is the substantially middle value of a critical angle range of 42 deg.-63 deg. and the apical angle at the prism part is set at 104 deg. so that the lights reflected on the first and second inclination interfaces impinge on the prism part at an incident angle of the substantially middle value of a critical angle range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink remaining amount detecting device for optically detecting the remaining amount of ink in an ink tank in an ink jet printer, and more particularly to a measure for improving the optical detection accuracy. Related to

[0002]

2. Description of the Related Art Conventionally, as this type of ink remaining amount detecting device, as disclosed in, for example, Japanese Patent Application Laid-Open No. 7-218321, a prism portion made of a light-transmitting material is integrated with an ink tank for storing ink. And a prism that reflects incident light from a light emitting element provided outside the ink tank toward the outside of the ink tank or refracts incident light toward the inside of the ink tank inside the ink tank. An interface and a second inclined interface for reflecting the light reflected by the first inclined interface inside the ink tank toward the outside of the ink tank or entering and refracting the inside of the ink tank toward the inside. And the first
The angle of the apex angle of the prism portion at which the inclined interface of the second and the second inclined interfaces intersect inside the ink tank is set to 90 °, the incident angle of the incident light with respect to the first inclined interface, and the second inclined interface By setting the incident angle of the reflected light with respect to
And the second inclined interface is sequentially reflected, and the reflected light is returned to a light receiving element provided outside the ink tank to be received.

That is, when there is no ink in the ink tank, the incident light from the light emitting element is reflected at the first inclined interface, and the reflected light is reflected at the second inclined interface and received by the light receiving element. Accordingly, it is detected that the remaining amount of the ink in the ink tank is not sufficient. On the other hand, when there is ink in the ink tank, the incident light from the light emitting element is refracted inward toward the inside of the ink tank without being reflected at the first inclined interface, and is not received by the light receiving element. It is detected that the remaining amount of ink is sufficient.

[0004]

When, for example, polypropylene is used as the material of the prism portion, the refractive index of light incident from the light emitting element is 1.49 for polypropylene and 1.33 for ink. , 1 in air. In this case, the condition under which the light is totally reflected at the interface between the dense medium and the coarse medium is limited to the time when light is irradiated from the dense medium to the coarse medium. , And polypropylene only when light is incident on the ink.

[0005] The condition for total reflection of light incident at an angle of incidence θ on the interface between polypropylene and air is such that a condition of sin θ> 1 / 1.49 is satisfied.
The incident angle θ needs to be set larger than 42.2 °. On the other hand, the condition for not totally reflecting the light incident at the incident angle θ with respect to the interface between the polypropylene and the ink is as follows:
In order to satisfy the relationship of sin θ <1.33 / 1.49, the incident angle θ needs to be set smaller than 63.2 °. From such a relationship, the critical angle range required to detect the presence or absence of the remaining amount of ink at the interface of the prism portion is 42 ° to 63 °.

For this reason, when the incident angle of light to the interface (first and second inclined interfaces) is set to 45 ° as in the above-described conventional device, the angle tolerance is only 3 °, and the light-emitting element In addition, if the prism portion (ink tank) is slightly misaligned, the light from the light emitting element may not return to the light receiving element even though the ink is depleted. Will be worse.

Therefore, as shown in FIG. 8, it is conceivable to set the incident angle of the light on the first inclined interface b to a substantially intermediate value, that is, 52 ° at which the maximum tolerance can be obtained with respect to the critical angle range. However, in the prism part a in which the angle of the apex angle is set to 90 °, the incident angle of the light on the second inclined interface c is 38 °, and the light totally reflected on the first inclined interface b is the second incident light. At the inclined interface c, the incident light is refracted inward (rightward in FIG. 8) of the ink tank, and the second inclined interface c
Cannot be totally reflected.

For this reason, as shown by the phantom line (two-dot chain line) in FIG. 8, in order to perform total reflection at the second inclined interface c ′, the prism portion a having an apex angle set to 94 ° or more is used.
Is required. However, since the light totally reflected at the second inclined interface c ′ is not parallel to the light from the light emitting element, the light totally reflected at the second inclined interface c ′ is received by the light receiving element. Therefore, it is necessary to accurately set the distance between the light receiving element and the prism part a '(the second inclined interface c'), and the tolerance of the distance between the light receiving element and the prism part a 'becomes extremely small. . In this case, if the incident angle of light with respect to the second inclined interface c ′ is set to 52 ° (substantially the middle value of the critical angle range) using the prism portion a ′ whose apex angle is set to 104 °, 2 inclined interface c
′ Enters the interface between the air and the prism portion a ′ at an angle of 28 °, is refracted at the interface at an outgoing angle of approximately 44 °, and is emitted. As the distance from 'increases, the distance from the light emitting element also increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and an object of the present invention is to increase the tolerance of the incident angle of light to the interface of the prism portion and the tolerance of the distance from the prism portion to increase the residual ink. An object of the present invention is to provide an ink remaining amount detecting device of an ink jet printer capable of increasing the amount detection accuracy.

[0010]

In order to achieve the above object, the present invention is based on the premise that an ink remaining amount detecting device for optically detecting the remaining amount of ink used in an ink jet printer is provided. A first inclined interface for refracting incident light from the light emitting element toward the inside of the ink tank, and an incident refracted light incident and refracted by the first inclined interface on the inside of the ink tank. A second inclined interface that reflects toward the outside of the ink tank or enters and refracts toward the inside of the ink tank;
A third inclined interface for reflecting the light reflected outward from the ink tank by the second inclined interface toward the outside of the ink tank or incident and refracting the reflected light toward the inside of the ink tank inside the ink tank; A fourth inclined interface that emits and refracts the reflected light reflected by the interface toward the outside of the ink tank so as to be parallel to the incident light from the light emitting element. Then, the angle of the first inclined interface is
While the angle of incidence of the incident refracted light with respect to the second inclined interface is set to be changed to a substantially intermediate value of a critical angle range in which the presence or absence of the remaining ink can be detected, the angle of the fourth inclined interface is set to The reflected light from the third inclined interface is set to be emitted and refracted almost in parallel with the incident light from the light emitting element. Further, the angle of the apex angle of the prism portion where the second inclined interface and the third inclined interface intersect inside the ink tank is determined by changing the incident refracted light from the first inclined interface and the angle from the second inclined interface. It is set so that the reflected light and the reflected light are respectively incident at a substantially intermediate value in a critical angle range in which the presence or absence of the ink remaining amount can be detected.

In this case, when there is no ink in the ink tank, the incident light from the light emitting element incident on the first inclined interface is incident and refracted at the first inclined interface, and the presence or absence of the remaining ink is detected. The incident angle of the incident refracted light with respect to the second inclined interface is changed so as to be substantially the middle value of the possible critical angle range, and the light is totally reflected at the second inclined interface.
The totally reflected light is incident on the third inclined interface at a substantially intermediate value within a critical angle range in which the presence or absence of the remaining ink can be detected, and is totally reflected. The light reflected from the light emitting element is changed so as to be emitted and refracted substantially parallel to the incident light from the light emitting element, and is received by the light receiving element, thereby detecting that there is no ink in the ink tank.

On the other hand, when there is ink in the ink tank, the incident light from the light emitting element incident on the first inclined interface is incident and refracted at the first inclined interface, so that the presence or absence of the remaining ink can be detected. The incident angle of the incident refracted light with respect to the second inclined interface is changed so as to have a substantially intermediate value within the critical angle range, and the incident light is incident and refracted toward the inside of the ink tank without being totally reflected at the second inclined interface. For this reason,
The incident light from the light emitting element is not received by the light receiving element, whereby it is detected that there is ink in the ink tank.

As described above, the incident angles of the incident light (incident refracted light and reflected light) on the second inclined interface and the third inclined interface of the prism portion are within a critical angle range in which the presence or absence of the remaining ink can be detected. Since it is set to a substantially intermediate value, the angle tolerance of the light becomes large, and even if the light emitting element and the prism portion (ink tank) are slightly misaligned, the light is within the angle tolerance (within the critical angle range). When there is no ink, the light from the light emitting element is surely returned to the light receiving element and received.

When there is no ink, the incident light from the light emitting element incident parallel to the bisector of the apex angle of the prism portion is substantially equal to the incident light from the light emitting element at the fourth inclined interface. Since the light is refracted and refracted in parallel and received by the light receiving element, the tolerance of the distance between the light receiving element and the prism part becomes large, and the light totally reflected at the third inclined interface is received by the light receiving element. It is not necessary to accurately set the distance between the element and the prism section (third inclined interface), and even if the distance between the light receiving element and the prism section is shifted, the incident light from the light emitting element is The light is reliably returned to the light receiving element and received.

This makes it possible to improve the accuracy of detecting the remaining amount of ink.

The following configuration is listed as a more specific configuration.

That is, when the same polypropylene as the material of the ink tank is used as the material of the prism portion, it is not necessary to separately form only the prism portion, and the entire ink tank is integrally formed of polypropylene. It is possible to reduce the cost.

Further, the apex angle of the prism portion is set to 104 °, and the intersection angle between the first inclined interface and the second inclined interface is set to 77 °.
In addition, the intersection angle between the third inclined interface and the fourth inclined interface is set to 7
When each is set to 7 °, when there is no ink in the ink tank, the incident light from the light emitting element incident at an incident angle of about 39 ° with respect to the first inclined interface is equal to the first inclined interface. , The incident angle of the incident refracted light with respect to the second inclined interface is changed to approximately 52 °, and the light is totally reflected at the second inclined interface. This totally reflected light is
The light is incident on the third inclined interface at about 52 ° and totally reflected,
When the light enters the fourth inclined interface at an angle of approximately 35 ° from the third inclined interface, the light is emitted and refracted at approximately 39 °, which is substantially parallel to the incident light from the light emitting element, at the fourth inclined interface. Received. This makes it possible to easily set a substantially intermediate value of the critical angle range in which the remaining amount of light of light with respect to each inclined interface when the prism portion is formed of polypropylene can be detected.

In particular, the following arrangement is provided as a means for informing the user that there is no ink in the ink tank.

That is, a pair of light-emitting elements is provided as a pair with a light-receiving element that receives refracted light emitted from the fourth inclined interface. Each time the plurality of ink tanks provided in the width direction of the recording medium are moved to the detection position, the remaining amount of the ink is individually detected by the light emitting element and the light receiving element, and the ink tank that has run out of ink is sent to the ink jet printer. When the display is provided on a display unit provided, one of the ink tanks is associated with the drive control of the ink carriage on which the plurality of ink tanks are mounted in the width direction of the recording medium by a set of light emitting elements and light receiving elements. It is possible to easily identify whether or not the ink has run out.
This can be reported to the user.

In addition, the remaining amount of ink in the plurality of ink tanks is detected by one set of the light emitting element and the light receiving element, thereby making it possible to reduce the size of the remaining ink amount detecting device. In addition, since the ink tank that has run out of ink is specified and displayed, erroneous operation due to an incorrect ink tank to be replaced is prevented.

In particular, the following configuration is specified to specify the arrangement of the prism portion.

That is, when the prism portion is provided on the bottom surface of the ink tank, each inclined interface can be provided continuously on the bottom surface of the ink tank, and the remaining amount of ink accumulated on the bottom surface side of the ink tank can be accurately determined. Can be detected.

On the other hand, when the prism portion is provided on the side surface of the ink tank, the ink mist that is scattered when ink droplets are ejected from the ink head is prevented from adhering to each inclined interface of the prism portion. It is possible to effectively prevent contamination of each inclined interface of the prism portion by mist.

[0025] In particular, the following configuration is specified to specify the arrangement of the light emitting element and the light receiving element.

That is, when the light emitting element and the light receiving element are arranged side by side in the transport direction of the recording medium, the first and second inclined interfaces of the prism portion and the third and fourth inclined interfaces of the prism section correspond to the recording medium. Since the ink tanks are provided side by side in the transport direction, the size of each ink tank can be reduced in the width direction of the recording medium and in the vertical direction of the ink head, and the inkjet printer can be made more compact.

In the case where the light emitting element and the light receiving element are juxtaposed in the vertical direction perpendicular to the width direction of the recording medium, the first and second inclined interfaces of the prism section and the third and fourth inclined interfaces are provided.
Are arranged side by side up and down, so that the size of each ink tank can be reduced in the width direction and the transport direction of the recording medium, and the inkjet printer can be made compact.

On the other hand, when the light emitting element and the light receiving element are arranged side by side in the width direction of the recording medium, the first part of the prism part is not provided.
And the second inclined interface and the third and fourth inclined interfaces are provided side by side in the width direction of the recording medium, so that the size of each ink tank can be reduced in the vertical direction of the ink head and the transport direction of the recording medium. As a result, the size of the ink jet printer can be reduced.

In particular, the following arrangements are provided for specifying the light beams of the light emitting element and the detecting element.

That is, when infrared light is applied as the light emitted by the light emitting element and the light received by the light receiving element, the infrared light passes through even if a filter is attached, so that noise due to disturbance light such as visible light is reduced. It is easily removed by the filter, and the detection accuracy of the remaining ink amount detection device can be further improved.

[0031]

Embodiments of the present invention will be described below with reference to the drawings.

In the present embodiment, a case will be described in which the paper stain prevention device according to the present invention is provided in a color ink jet printer.

First, the configuration of the color ink jet printer 1 according to the present embodiment will be described with reference to FIGS. FIG. 1 is a perspective view showing the appearance of the color inkjet printer 1. FIG. 2 is a diagram showing the internal structure of the color inkjet printer 1.

The color ink jet printer 1 is provided with a paper feed tray 3 on the front side (right side in FIG. 1) of a cabinet 2 as a main body, and above the paper feed tray 3 on the front side. A paper discharge tray 4 is provided for sequentially receiving recording paper P as a recording medium discharged from the cabinet 2. On the paper feed tray 3,
A positioning member 31 for positioning a paper feed position of the recording paper P as a mounted recording medium is provided.

On the other hand, as shown in FIG.
, From the paper feed tray 3 to the paper discharge tray 4,
A pickup roller 11, a paper feed roller 12, a substantially U-shaped transport path 13, a PS roller 14, an ink carriage 17, and a paper discharge roller 18 are provided in this order.

As shown in FIG. 3, the ink carriage 17 is supported by the driving mechanism 10. The driving mechanism 10 includes a driving pulley 10b rotated forward and reverse by a driving motor 10a, a driven pulley 10c, and a belt 10d stretched between the driving pulley 10b and the driven pulley 10c.
(Appears in FIG. 4). As shown in FIG. 4, the forward path (lower side in FIG. 3) of the belt 10d between the driving pulley 10b and the driven pulley 10c is fixed to the ink carriage 17, and is driven by the driving motor 10a. The ink carriage 17 (ink head 16) can reciprocate along the guide shaft 10e in the direction perpendicular to the paper surface (main scanning direction).

The ink carriage 17 has an ink tank 15 mounted thereon and an ink head 16. Specifically, as shown in FIGS. 3 and 4, Y (yellow),
Four ink tanks 15a to 15 that individually store M (magenta), C (cyan), and Bk (black) inks
5d are mounted in order in the main scanning direction. Further, inside the ink head 16, these tanks 15a are provided.
15d are provided with a plurality of nozzles (not shown) that are individually connected via supply paths (not shown).

As shown in FIG. 3, the present color ink jet printer 1 has a control device 5 for controlling each part. The processes and operations of the color inkjet printer 1 described below are performed by the control device 5 unless otherwise specified.
Shall control.

When the printing operation of the color inkjet printer 1 is started, first, one sheet of the recording paper P placed on the paper feed tray 3 is picked up by the pickup roller 11.
, And guided to the transport path 13 by the paper feed roller 12. Thereafter, the recording paper P is conveyed to an image forming position 19 facing the ink carriage 17. Then, when the recording paper P passes through the image forming position 19, inks of different colors are individually ejected in a droplet form from each nozzle provided in the ink head 16 based on the position of the recording paper P and the print data. The recording paper P
The image formation is performed for.

The image forming operation will be specifically described.
When the recording paper P is transported to the image forming position 19, ink is ejected from each nozzle toward the recording paper P while the ink carriage 17 moves in the direction of the arrow I (main scanning direction) in FIGS. Thus, an image is formed on the recording paper P. When the ink carriage 17 moves to the other end in the width direction of the recording sheet P, the recording sheet P is moved (conveyed) by a predetermined amount (arrows in FIGS. 3 and 4).
After moving in the sub-scanning direction indicated by III), stop.
Then, the ink carriage 17 corresponds to the arrow in FIGS.
Image formation is performed while moving in the II direction (main scanning direction). In this manner, the image forming operation by the movement of the ink carriage 17 in the main scanning direction and the feeding operation of the recording paper P are alternately performed to form the image on the entire recording paper P.

The recording paper P on which an image is formed over substantially the entire surface is discharged toward the discharge tray 4 by the discharge rollers 18. As a result, the recording paper P on which a predetermined image has been formed is discharged to the discharge tray 4 in a face-up state (a state in which the image forming surface faces upward).

FIGS. 5 to 5 show a characteristic part of the present invention.
As shown in FIG. 7, the present color inkjet printer 1
Includes an ink remaining amount detecting device 6 that optically detects the remaining amount of ink stored in each of the ink tanks 15a to 15d.

As shown in FIGS. 6 and 7, the ink remaining amount detecting device 6 includes a prism 61 provided at the bottom of each of the ink tanks 15a to 15d, and a recording paper P.
The light emission provided outside the one end in the width direction of the recording paper P (the left end of the conveyance area Z shown in FIGS. 3 and 4) orthogonal to the conveyance direction (the direction of the arrow III shown in FIGS. 3 and 4). The element 62 and the light receiving element 6 arranged in the conveying direction of the recording paper P
3 and the ink tanks 15a to 15 having a small remaining amount of ink.
notification means 64 for notifying d. As a material of the prism portion 61, each of the ink tanks 15a to 15
The ink tanks 15a to 15d are integrally formed at the center of the bottom with the same polypropylene as the material d. In this case, the bottom of each of the ink tanks 15a to 15d is exposed downward via the ink carriage 17.

The prism portion 61 of each of the ink tanks 15a to 15d makes incident light vertically upwardly incident from the light emitting element 62 incident on the outer surfaces of the ink tanks 15a to 15d inwardly of the ink tank (upward in FIG. 6). A first inclined interface 61a to be refracted, and the first inclined interface 61
The incident refracted light incident and refracted by the
A second inclined interface 61b that reflects toward the outside of the ink tank (rightward in FIG. 6) or enters and refracts toward the inside of the ink tank (upward in FIG. 7) on the inner surfaces a to 15d.
And the reflected light reflected outward from the ink tank by the second inclined interface 61b.
And a third inclined interface 61c that reflects toward the outside of the ink tank (downward in FIG. 6) or enters and refracts toward the inside of the ink tank (rightward in FIG. 6).
The reflected light reflected by the inclined interface 61c is directed outward from the ink tank so as to be parallel to the incident light from the light emitting element 62 on the outer surfaces of the ink tanks 15a to 15d (FIG. 6).
In this case, the fourth inclined interface 6 which emits and refracts vertically downward.
1d.

The apex angle of each prism portion 61, that is, the intersection angle between the second inclined interface 61b and the third inclined interface 61c that intersect each other on the inner surface of each of the ink tanks 15a to 15d is the first inclined interface. 104 ° so that the incident refracted light from 61a and the reflected light from the second inclined interface 61b are respectively incident at a substantially intermediate value 52 ° of a critical angle range of 42 ° to 63 ° at which the presence or absence of the remaining ink can be detected. Is set to The second inclined interface 61b and the third inclined interface 61c are each inclined by 38 ° with respect to the horizontal bottom surface of each of the ink tanks 15a to 15d. On the other hand, the first inclined interface 61a inclined on the outer surface of each of the ink tanks 15a to 15d has a critical angle range of 42 ° in which the incident angle of the incident refracted light with respect to the second inclined interface 61b can be detected by detecting the presence or absence of the remaining ink. 39 degrees with respect to the horizontal bottom surface of each of the ink tanks 15a to 15d so as to be changed to a substantially intermediate value of 52 ° to 63 °.
° is inclined. Further, each of the ink tanks 15a to 15d
A fourth inclined interface 61d that is inclined on the outer surface of the light-receiving element 63 emits the reflected light from the third inclined interface 61c substantially parallel to the incident light from the light emitting element 62 and causes the light receiving element 63 to receive the light. The tanks are inclined by 39 ° with respect to the horizontal bottom surfaces of the tanks 15a to 15d. The intersection angle between the first inclined interface 61a and the second inclined interface 61b and the intersection angle between the third inclined interface 61c and the fourth inclined interface 61d are each set to 77 °.

The light emitting element 62 is provided as a pair with the light receiving element 63. The light emitted by the light emitting element 62 and the light received by the light receiving element 63 are infrared rays. In this case, the time required for the infrared light emitted from the light emitting element 62 to be received by the light receiving element 63, that is, the detection time, is the light emitting element 62 and the light receiving element 63 generated when each of the ink tanks 15a to 15d moves. Is very short enough to be performed sufficiently within the time difference at the time of passing.

The notifying means 64 shown in FIG. 3 has a display unit (not shown) provided on the upper surface of the cabinet 2 of the color ink jet printer 1.

In the control device 5, a plurality of ink tanks 15
drive mechanism 1 with ink carriage 17 carrying a to 15d
When the recording paper P is driven by 0, the moving amount (driving amount) of the recording paper P in the width direction is grasped.
The positions of the plurality of ink tanks 15a to 15d which are moved in the width direction of the recording paper P by the driving mechanism 10 are clearly defined. That is, when the ink carriage 17 is moved by the driving mechanism 10, the ink tanks 15a to 15d sequentially pass through the light emitting element 62 and the light receiving element 63.
Are individually defined in order in accordance with the amount of movement by the drive mechanism 10.

Then, the ink remaining amount detecting device 6 moves the ink carriage 17 on which the plurality of ink tanks 15a to 15d are mounted to one side in the width direction of the recording paper P by the driving mechanism 10 (indicated by an arrow II in FIGS. 3 and 4). The amount of ink remaining in each of the ink tanks 15a to 15d is individually detected in association with the drive control of the control device 5 for driving in the main scanning direction, and the control device 5 determines which ink tank has run out of ink.
The information is displayed on the display unit through the notifying means 64 from.

As described above, in this embodiment, the image formation on the recording paper P is completed, and the ink carriage 17 on which the plurality of ink tanks 15a to 15d are mounted is moved by the driving mechanism 10 to one side in the width direction of the recording paper P (see FIG. When driven in the main scanning direction (indicated by arrow II in FIGS. 3 and 4), each of the ink tanks 15a to 15d is
The remaining amount of ink in each is detected individually.

In this case, the vertex angle of the prism portion 61 is 104
°, the intersection angle between the first inclined interface 61a and the second inclined interface 61b is set to 77 °, and the intersection angle between the third inclined interface 61c and the fourth inclined interface 61d is set to 77 °. Therefore, as shown in FIG.
When there is no ink in the first inclined interface 61a, the incident light from the light emitting element 62, which is incident on the first inclined interface 61a in parallel with the bisector of the apex angle of the prism portion 61, is incident on the first inclined interface 61a. Is incident at an incident angle of 39 °, and is incident and refracted at the first inclined interface 61a, the incident angle of the incident refracted light to the second inclined interface 62b becomes a critical angle range of 42 ° to 63 at which the remaining ink amount can be detected. The angle is changed to 52 ° so as to be a substantially intermediate value of °, and the light is totally reflected at the second inclined interface 61b. The totally reflected reflected light is incident on the third inclined interface 61c at a substantially intermediate value 52 ° of a critical angle range of 42 ° to 63 ° in which the presence or absence of the remaining ink can be detected, and is totally reflected. Third inclined interface 61c with respect to inclined interface 61d
Incident at about 35 ° from the fourth inclined interface 61
d, the reflected light from the third inclined interface 61c is changed so as to be emitted and refracted almost parallel to the incident light from the light emitting element 62, and is received by the light receiving element 63, so that the ink is stored in each of the ink tanks 15a to 15d. Is detected.

On the other hand, as shown in FIG. 7, when there is ink in each of the ink tanks 15a to 15d, the incident light from the light emitting element 62 incident on the first inclined interface 61a at an incident angle of 39 ° is: When the incident light is refracted at the first inclined interface 61a, the incident angle of the incident refracted light with respect to the second inclined interface 62b becomes a critical angle range 42 ° in which the remaining amount of the ink can be detected.
Although the angle is changed to 52 ° so as to be a substantially intermediate value of about 63 ° to 63 °, since the ink is present in the ink tanks 15a to 15d, the inside of the ink tank is not reflected at the second inclined interface 61b (see FIG. 7). (Upward). For this reason, the incident light from the light emitting element 62 is not received by the light receiving element 63, so that each ink tank 15
It is detected that there is ink in a to 15d.

As described above, the angle of incidence of the incident light (incident refracted light and reflected light) on the second inclined interface 61b and the third inclined interface 61c of the prism portion 61 is determined by the critical angle range 42 in which the amount of remaining ink can be detected. Since the angle is set to approximately the intermediate value of 52 ° to 52 °, the angle tolerance of light becomes large, and the light emitting element 62 and the prism portion 61 (the ink tanks 15a to 15d) are slightly misaligned. Is sufficiently contained within the angle tolerance of light (critical angle range of 42 ° to 63 °), and when there is no ink, the light from the light emitting element 62 returns to the light receiving element 63 without fail and is received. .

When there is no ink, the light emitting element 62 incident parallel to the bisector of the apex angle of the prism portion 61
From the light emitting element 62 is emitted and refracted at the fourth inclined interface 61d almost in parallel with the incident light from the light emitting element 62 and received by the light receiving element 63.
1 (the bottom surface of each of the ink tanks 15a to 15d) has a large tolerance, and when the light totally reflected at the third inclined interface 61c is received by the light receiving element 63, the light receiving element 63 and the prism section 61 are received. There is no need to accurately set the distance between the light receiving element 63 and the third light receiving element 63c.
Even if the distance between the prism part 61 and
The incident light from the light emitting element 62 returns to the light receiving element 63 without fail and is received.

Thus, it is possible to easily set the approximate intermediate value of the critical angle range 42 ° to 63 ° at which the remaining amount of infrared light ink can be detected with respect to each of the inclined interfaces 61a to 61d of the polypropylene prism portion 61 to 52 °. Thus, the accuracy of detecting the remaining amount of ink can be improved.

Further, since the prism portion 61 is integrally formed of the same polypropylene as the material of the ink tank, it is not necessary to separately form only the prism portion 61, and each of the ink tanks 15a to 15c having the prism portion 61 is not required. 1
The processing cost of 5d can be reduced.

The plurality of ink tanks 15a to 15
Each of the ink tanks is associated with the drive control of the control device 5 that drives the ink carriage 17 on which the recording paper d is placed in the width direction of the recording paper P (the main scanning direction indicated by the arrow II in FIGS. 3 and 4) by the driving mechanism 10. Since the remaining amounts of ink of the ink tanks 15a to 15d are individually detected,
Whether the 5d ink has run out can be easily specified. In addition, the ink tank 15a that has run out of ink
-15d is notified from the control device 5 to the notifying means 64.
Is displayed on the display unit, and the user can easily specify the ink tank 15a to 15d. Further, the remaining amount of ink in the four ink tanks 15a to 15d is detected by one set of the light emitting element 62 and the light receiving element 63, so that the remaining ink amount detecting device 6 can be made compact.

Further, since the prism portion 61 is provided on the bottom surface of each of the ink tanks 15a to 15d, it is possible to continuously provide the inclined interfaces 61a to 61d on the inner surface and the outer surface of the bottom surface of the ink tank. It is possible to accurately detect the amount of ink remaining on the bottom surface side of the ink tanks 15a to 15d.

Further, since the light emitting element 62 and the light receiving element 63 are arranged side by side in the conveying direction of the recording paper P, each ink tank in the main scanning direction and the vertical direction of the ink carriage 17 perpendicular to the conveying direction of the recording paper P. 15a-1
By reducing the size of 5d, the inkjet printer 1 can be made more compact.

Further, since infrared light is applied as the light emitted from the light emitting element 62 and the light received by the light receiving element 63, it is possible to use a filter that transmits infrared light, and it is possible to use a filter that transmits visible light or the like. Noise due to disturbance light is easily removed by the filter, and the detection accuracy of the remaining ink amount detection device 1 can be further improved.

It should be noted that the present invention is not limited to the above embodiment, but encompasses various other modifications.
For example, in the present embodiment, the angle of incidence of the refracted light incident on the second inclined interface and the angle of incidence of the reflected light on the third inclined interface are each a critical angle range of 42 ° to 63 in which the presence or absence of the remaining ink can be detected. The angle was set to 52 ° so as to be a substantially intermediate value of °, but is not particularly limited as long as it is near an approximately intermediate value of the critical angle range of 42 ° to 63 ° such as 53 °.

In this embodiment, the prism portion 61 is provided on the bottom surface of each of the ink tanks 15a to 15d, but the prism portion may be provided on the side surface of each of the ink tanks. It is possible to prevent ink mist that scatters when ink droplets are ejected from being adhered to each inclined interface of the prism unit, and it is possible to effectively prevent contamination of each inclined interface of the prism unit by ink mist.

Further, in this embodiment, the light emitting element and the light receiving element are arranged in the conveying direction of the recording paper P. However, the light emitting element and the light receiving element may be arranged in the vertical direction perpendicular to the width direction of the recording paper. In this case, the first and second inclined interfaces of the prism portion and the third and fourth inclined interfaces are provided vertically one above the other, and each ink is provided in the width direction and the transport direction of the recording paper. By reducing the size of the tank, the size of the ink jet printer can be reduced. On the other hand, a light-emitting element and a light-receiving element may be provided side by side in the main scanning direction of the ink carriage. In this case, the first and second inclined interfaces of the prism portion and the third and fourth inclined interfaces are provided. Are arranged side by side in the width direction of the recording paper, so that the size of each ink tank can be reduced in the vertical direction of the ink head and in the main scanning direction, and the inkjet printer can be made compact. .

Further, in this embodiment, the light emitting element 62 and the light receiving element 63 are provided outside one end in the width direction of the recording paper P.
A light emitting element and a light receiving element may be provided inside the recording paper in the width direction.

[0065]

As described above, according to the present invention, the incident angle of the incident refracted light with respect to the second inclined interface in the prism portion of the ink tank is determined to be substantially the intermediate value of the critical angle range in which the presence or absence of the remaining ink can be detected. The angle of the first inclined interface is set so as to change the angle of the first inclined interface, and the angle of the fourth inclined interface is set so that the reflected light from the third inclined interface is emitted and refracted almost parallel to the incident light from the light emitting element. The top of the prism portion is set so that the refracted light incident from the first inclined interface and the reflected light from the second inclined interface are respectively incident at substantially intermediate values in a critical angle range in which the presence or absence of the remaining ink can be detected. By setting the angle, the angle tolerance of the light can be increased, and the accuracy of detecting the remaining amount of ink can be improved.

As a more specific configuration, by applying the same polypropylene as the material of the ink tank to the material of the prism portion, the entire ink tank is integrally formed with the prism portion with polypropylene, thereby reducing the processing cost. Can be achieved.

The apex angle of the prism portion is set to 104 °, and the intersection angle between the first inclined interface and the second inclined interface is set to 77 °.
In addition, the intersection angle between the third inclined interface and the fourth inclined interface is set to 7
By setting each of the angles to 7 °, it is possible to easily set a substantially intermediate value of the critical angle range of light with respect to each inclined interface in which the amount of remaining ink can be detected when the prism portion is formed of polypropylene.

Each time a plurality of ink tanks are moved in the width direction of the recording medium, the remaining amount of the ink is individually detected by a set of light emitting element and light receiving element, and the ink tank which has run out of ink is displayed on the display unit of the ink jet printer. In this case, the ink tank having no ink can be easily specified in association with the drive control of the ink carriage in the recording medium width direction, and the user can be notified of the ink tank. In addition, the detection of the remaining amount of ink by one set of the light emitting element and the light receiving element can reduce the size of the remaining ink amount detecting device, and prevent erroneous operation due to erroneous replacement of the ink tank according to the display on the display unit. be able to.

In particular, by providing the prism portion on the bottom surface of the ink tank, each inclined interface is continuously provided on the bottom surface of the ink tank, and the remaining amount of ink can be accurately detected.

On the other hand, by providing the prism portion on the side surface of the ink tank, adhesion of ink mist to each inclined interface of the prism portion is avoided, and contamination of each inclined interface of the prism portion by ink mist is effectively prevented. can do.

In particular, by arranging the light emitting element and the light receiving element in the conveying direction of the recording medium, the size of each ink tank is reduced in the width direction of the recording medium and the vertical direction of the ink head, and the ink jet printer can be made compact. Can be planned.

Further, by arranging the light emitting element and the light receiving element in the vertical direction orthogonal to the width direction of the recording medium, the size of each ink tank in the width direction and the conveying direction of the recording medium can be reduced, and the size of the ink jet printer can be reduced. Can be achieved.

On the other hand, by arranging the light emitting element and the light receiving element side by side in the width direction of the recording medium, the size of each ink tank in the vertical direction of the ink head and the conveying direction of the recording medium can be reduced. Can be achieved.

Further, by applying infrared light as a light beam to the light emitting element and the light receiving element, noise due to disturbance light such as visible light can be easily removed by a filter, and the detection accuracy of the ink remaining amount detecting device can be further improved. Can be.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a color inkjet printer including an ink remaining amount detecting device according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing the internal configuration of a color inkjet printer.

FIG. 3 is a diagram illustrating a configuration near a driving mechanism as viewed from a conveyance direction of a recording sheet.

FIG. 4 is a perspective view showing an ink carriage and its periphery.

FIG. 5 is a perspective view of an ink tank.

FIG. 6 is a cross-sectional view of a prism unit showing a light reflection state when light returns from a light emitting element to a light receiving element.

FIG. 7 is a cross-sectional view of a prism portion showing a direction of light when light does not return from the light emitting element to the light receiving element.

FIG. 8 is a cross-sectional view of a prism portion showing a light reflection state according to a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Color inkjet printer (inkjet printer) 15a-15d Ink tank 6 Ink remaining amount detecting device 61 Prism part 61a First inclined interface 61b Second inclined interface 61c Third inclined interface 61d Fourth inclined interface 62 Light emitting element 63 Light receiving element P Recording paper (recording medium)

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroyuki Ishikura 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka F-term (reference) 2C056 EA29 EB20 EB52 EC26 2F014 AB01 AB02 AB03 FA02

Claims (10)

[Claims] An ink remaining amount detection device for optically detecting the remaining amount of ink used in an ink jet printer, wherein a prism portion is provided in an ink tank, and the prism portion is configured to receive incident light from a light emitting element. A first inclined interface that is incident and refracted toward the inside of the ink tank; and an incident refracted light that is incident and refracted by the first inclined interface is reflected inside the ink tank toward the outside of the ink tank or incident and refracted toward the inside of the ink tank. A second inclined interface, and a third inclined surface that reflects the light reflected outward from the ink tank by the second inclined interface inside the ink tank toward the outside of the ink tank or incident and refracted toward the inside of the ink tank. An ink interface so that the reflected light reflected by the third inclined interface is parallel to the incident light from the light emitting element. And a fourth inclined interface that emits and refracts outward in the direction of the angle. The angle of the first inclined interface is determined based on the angle of incidence of the incident refracted light with respect to the second inclined interface. The angle of the fourth inclined interface is set so as to be changed to a substantially intermediate value of the angular range, and the angle of the fourth inclined interface is such that the reflected light from the third inclined interface is emitted and refracted almost parallel to the incident light from the light emitting element. The angle of the apex angle of the prism portion at which the second inclined interface and the third inclined interface intersect inside the ink tank is determined by the angle of the incident refracted light from the first inclined interface and the angle of the second inclined interface. An ink remaining amount detecting device for an ink jet printer, wherein the reflected light from the inclined interface is set so as to be incident at a substantially intermediate value of a critical angle range in which the presence or absence of the ink remaining amount can be detected. 2. The ink remaining amount detecting device for an ink jet printer according to claim 1, wherein the same polypropylene as the material of the ink tank is applied as a material of the prism portion. 3. An apex angle of the prism portion is 104 °, and an intersection angle between the first inclined interface and the second inclined interface is 77 °.
In addition, the intersection angle between the third inclined interface and the fourth inclined interface is 7
3. The apparatus according to claim 2, wherein the angle is set to 7 [deg.]. 4. The light-emitting element is provided as a pair with a light-receiving element that receives refracted light emitted from a fourth inclined interface, and the light-emitting element and the light-receiving element are provided in a plurality in a width direction of a recording medium. Each time the provided ink tank is moved to the detection position, the remaining amount of ink is individually detected, and the ink tank that has run out of ink is displayed on a display unit provided in the inkjet printer. The apparatus according to claim 1, wherein the remaining amount of the ink is detected by an ink jet printer. 5. The apparatus according to claim 1, wherein the prism unit is provided on a bottom surface of the ink tank. 6. The apparatus according to claim 1, wherein the prism portion is provided on a side surface of the ink tank. 7. The apparatus according to claim 4, wherein the light emitting element and the light receiving element are arranged side by side in a conveying direction of the recording medium. 8. The apparatus according to claim 4, wherein the light emitting element and the light receiving element are arranged in a vertical direction orthogonal to a width direction of the recording medium. 9. The light-emitting element and the light-receiving element are arranged side by side in a width direction of a recording medium.
An ink remaining amount detecting device for an ink jet printer according to claim 1. 10. The apparatus according to claim 4, wherein infrared light is applied as the light emitted by the light emitting element and the light received by the light receiving element. .