JP2009131968A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve possibilities of accidentally staining an encoder scale and spoiling the encoder scale itself when a user performs an operation by putting the hand in an apparatus in the image forming apparatus in which the action of a carriage is controlled by providing an encoder sensor on the carriage mounting a printing head and by hanging the encoder scale whose position is detected by the encoder sensor on a machine frame. <P>SOLUTION: The encoder scale 8 detected by the encoder sensor 4 provided on the carriage 1 is fixed on a supporting member 7 provided so as to be movable straightly to the machine frame (side plate) m, and the encoder scale 8 is provided so as to come into contact with and to separate from the encoder sensor 4. When the user performs the operation by putting the hand in the apparatus M, the encoder scale 8 is separated from the encoder sensor 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus including a print execution unit that is movable in a direction orthogonal to a plan view in the conveyance direction of a recording material, and more particularly to an encoder scale mounting structure that measures the position of the print execution unit.

2. Description of the Related Art Conventionally, there is an image forming apparatus that feeds and prints a recording material while reciprocally moving a carriage mounted with a print head in a direction perpendicular to the conveyance direction of the recording material.
In this image forming apparatus, an encoder sensor is provided on the carriage, and an encoder scale as an object to be detected by the encoder sensor is installed on the machine frame so that the position of the carriage can be measured, thereby realizing an accurate printing operation. is doing.
As described above, the image forming apparatus measures the position of the carriage using the encoder scale. The conventional attachment structure of the encoder scale will be described below. For example, the substantially L-shaped metal fittings are back to back. In some cases, an encoder scale is sandwiched between them, and the bracket is fixedly attached to the printer body (machine frame) (see, for example, Patent Document 1).
As another example, the top of a plate-like member is bent into a substantially U-shape, and a pair of side plates (machines) arranged opposite to each other are provided with a carriage holding portion formed so as to shield both sides of the bent top. There is one in which an encoder scale is installed in the top (see, for example, Patent Document 2).
JP 2002-205435 A (Page 4, FIG. 11) JP-A-8-230265 (2nd page, FIG. 1)

However, the conventional image forming apparatuses described above have the following problems.
That is, in the image forming apparatus disclosed in Patent Document 1, the encoder scale is fixed to the printer main body (machine frame) when a user puts a hand inside the machine and performs work such as when a paper jam occurs in the apparatus. As a result, the encoder scale may be accidentally touched and soiled, or the encoder scale itself may be damaged.
If the surface of the encoder scale becomes dirty or damaged, a detection failure may occur and the carriage may not operate normally.

In the image forming apparatus disclosed in Patent Document 2, a carriage holding unit is installed on a pair of side plates (machine frame) arranged opposite to each other, and an encoder scale is installed in a bent top portion. It used many, and the place where an encoder scale was installed was limited.
The encoder scale can be measured more accurately if it is installed as close to the carriage drive center as possible. However, according to this device, the encoder scale is arranged in the rearward direction on the upper side of the carriage at a position away from the drive center. There was a problem in this regard.
Accordingly, the present invention has been made in view of such a situation, and an object thereof is to provide an image forming apparatus capable of solving the above-described problems.

In order to achieve the above technical problem, the image forming apparatus according to the present invention employs the following technical means.
That is, an image forming apparatus according to a first aspect includes a print execution unit that is movable in a width direction orthogonal to the conveyance direction of the recording material, an encoder sensor attached to the print execution unit, and a scale detected by the encoder. An image forming apparatus configured to perform position measurement of the print execution unit based on position information of the scale detected by the encoder sensor, wherein the encoder scale is connected to the encoder sensor. It is attached to the machine frame so that it can be moved away from the machine.
According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, further comprising: a support member that is provided on the machine frame so as to be linearly movable, and that supports the encoder scale by fixing both ends of the encoder scale. And

According to a third aspect of the present invention, there is provided the image forming apparatus according to the second aspect, further comprising an operation lever having an intermediate portion pivotally supported by the machine frame and having one end engaged with the support member, and the other end of the operation lever is pushed. Thus, the encoder scale is configured to be separated from the encoder sensor.
According to a fourth aspect of the present invention, in any one of the first to third aspects, the image forming apparatus includes an exterior cover provided with an open / close door, and the operation lever is disposed inside the open / close door. And
An image forming apparatus according to a fifth aspect is the image forming apparatus according to the first or second aspect, wherein the encoder scale is brought close to the encoder sensor in response to a closed state of the open / close door and the open / close door is closed. And a contact / separation mechanism for separating the encoder scale from the encoder sensor in response to an open state of the door.
An image forming apparatus according to a sixth aspect is the carriage according to any one of the first to fifth aspects, wherein the print execution unit is mounted with a liquid droplet ejection head that ejects liquid droplets onto the recording material to form an image. It is characterized by being.

According to the present invention, the encoder scale for measuring the position of the print execution unit is installed on the machine frame so as to be able to come in contact with and away from the encoder sensor. Since the encoder scale can be separated from the encoder sensor, the encoder scale that may be accidentally touched during the operation can be moved to a safe position for the operation.
In addition, the space around the encoder scale is not occupied, and the location where the encoder scale is installed is not limited, so that a layout capable of highly accurate position measurement can be achieved.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.
First, an outline of the image forming apparatus M according to the present embodiment will be described with reference to FIGS. 1 and 2.
The image forming apparatus M according to the present embodiment includes a transport mechanism (not shown) that transports the recording material P, a carriage 1 (print execution unit) that includes a droplet discharge head (not shown), and the carriage. An endless timing belt 2 fixedly attached to the back surface of the recording medium P and rotatably supported in a direction perpendicular to the conveyance direction of the recording material P, and a motor (not shown) for rotating the timing belt 2. The guide shaft 3 installed in parallel with the timing belt 2 and loosely inserted on the rear surface of the carriage 1, the encoder sensor 4 provided on the rear surface of the carriage 1, and installed in parallel with the guide shaft 3 and detected by the encoder sensor 4. And an encoder scale 8 for measuring the position of the carriage 1.

The image forming apparatus M is a so-called ink jet printer that operates according to image data. The recording material P is fed out by a transport mechanism, and the timing belt 2 is rotated by a motor so as to be orthogonal to the transport direction of the recording material P in a plan view. The carriage 1 is reciprocated, and ink droplets are ejected from the droplet ejection head as the carriage 1 reciprocates, and printing is performed on the recording material P.
In addition, the image forming apparatus M reads the encoder scale 8 installed in parallel with the guide shaft 3 with the encoder sensor 4 provided on the carriage 1, thereby grasping the position of the carriage 1 and accurately operating the carriage 1. It comes to control.

Hereinafter, each embodiment of the attachment structure of the encoder scale 8 for measuring the position of the carriage 1 (printing execution unit), which is the main part of the present invention, will be described in detail.
(Embodiment 1)
As shown in FIGS. 1 and 2, the image forming apparatus M according to the first exemplary embodiment includes an encoder sensor 4, an encoder scale unit 5, and an exterior cover 6.
The encoder sensor 4 is a transmissive photosensor having a well-known structure in which a slit-like opening 4a is formed and its outer shape is substantially gate-shaped. The encoder sensor 4 is fixed to the rear side of the carriage 1 so that the opening 4a faces upward. It is worn.
The encoder scale unit 5 includes a support member 7, an encoder scale 8, and an operation lever 9.

The supporting member 7 connects a pair of substantially rectangular sliding portions 7b each having a mountain-shaped supporting portion 7a formed on one side surface thereof, and upper portions on the other side surfaces of the pair of sliding portions 7b arranged to face each other. The strip-shaped connecting portion 7c and the ear portion 7d that protrudes outward in the horizontal direction from the lower portion of one side surface of the sliding portion 7b are bent into a substantially U shape. ing.
In addition, a long hole 7e having a required length extends from the vicinity of the starting point of the connecting portion 7c to a position immediately below the sliding portion 7b.
In the support member 7 formed in this way, the back surface of the sliding portion 7b is in contact with the outer surface of a pair of substantially L-shaped side plates m (machine frame) in which the upper side m1 and the lower side m2 are connected by the vertical side m3. The mountain-shaped support part 7a is straddled so as to protrude in the horizontal direction from the vertical side m3 of the side plate m, and a set of two guide pins 10 are inserted through the long holes 7e. Thus, the support member 7 is slidable in the vertical direction with respect to the side plate m.
The encoder scale 8 is formed in a band plate shape having slit holes 8a arranged in parallel, and both ends thereof are fixed to the pair of support portions 7a so that a midway portion thereof is loosely inserted into the opening 4a of the encoder sensor 4. Has been. As described above, the encoder scale 8 is installed on the side plate m via the support member 7 that is slidable in the vertical direction.

The operation lever 9 is formed in a substantially L shape so that one end side can come into contact with the bottom surface of the ear portion 7d and the other end side can protrude upward from the lower side m2 of the side plate m. The ridge is pivotally attached to the side plate m.
The operation lever 9 configured in this manner pushes the other end side downward, so that one end side rises with the support shaft 11 as a rotation fulcrum and pushes up the ear portion 7d of the support member 7, whereby the encoder scale 8 Is separated from the encoder sensor 4.
Further, in order to maintain this separated state, the side plate m is provided with a convex portion m4 for latching the other end side of the depressed operating lever 9.
The convex portion m4 has a height that can be overcome by pushing down downward while slightly elastically deforming the other end of the operating lever 9 outward (applying a slight force outward). The other end side of the lever 9 gets over the convex portion m4 so that the other end side of the operation lever 9 is hooked on the convex portion m4.
The operation lever 9 is provided only on one side plate m, but may be provided on both side plates m.

The exterior cover 6 is a constituent member that forms the appearance design of the image forming apparatus M, and has each constituent part related to image formation inside.
In the exterior cover 6, a part of the outer cover 6 that is directly above the encoder scale unit 5 is provided with a single-open door 12 that can be opened and closed toward the rear side of the apparatus via a hinge (not shown). Replacement of the cartridge, removal of the jammed recording material P, and the like can be easily performed.
In the image forming apparatus M according to the first embodiment configured as described above, when the ink cartridge is replaced or the recording material P is removed due to a paper jam, the opening / closing door 12 is first opened to open the encoder scale unit 5. Exposed.

Next, the other end side of the operation lever 9 is gripped and pushed downward while applying a slight force toward the outside so that the encoder scale 8 is separated from the encoder sensor 4 so that the encoder scale 8 does not fall. The other end is hooked on a convex portion m4 provided on the side plate m.
If such a state is secured, operations such as replacement of the ink cartridge and removal of the recording material P due to paper jam are performed.
When the operation is completed, the other end side of the operation lever 9 is gripped, pulled upward while applying a slight force toward the outside, and the encoder scale 8 is loosely inserted into the opening 4 a of the encoder sensor 4. At this time, the encoder scale 8 stops without contacting the encoder sensor 4 via the support member 7 because of the arrangement relationship between the two pairs of guide pins 10 and the long holes 7e.

As described above, in the image forming apparatus M according to the first embodiment, the encoder scale 8 is installed on the machine frame so that the encoder scale 8 can be brought into and out of contact with the encoder sensor 4, and the user puts his / her hand inside the apparatus to perform work. In addition, since the encoder scale 8 can be separated from the encoder sensor 4, the encoder scale 8 that may be accidentally touched during the work can be moved to a safe position before the work can be performed. .
In addition, since the space around the encoder scale 8 is not occupied and the location where the encoder scale 8 is installed is not limited, a layout capable of highly accurate position measurement can be achieved.
Further, since the operation lever 9 for operating the encoder scale 8 is provided inside the exterior cover 6, the encoder scale 8 can be moved only when the door 12 is opened. For example, the image forming apparatus M It is possible to prevent the encoder scale 8 from being moved during the operation.
In the image forming apparatus M according to the first embodiment, the operation lever 9 is provided to improve the convenience. However, even if the operation lever 9 is not provided, the connection portion 7c can be held and lifted. For example, the encoder scale 8 can be separated from the encoder sensor 4.

(Embodiment 2)
The image forming apparatus M according to the second embodiment shows another aspect of the encoder scale unit 5 as shown in FIGS. 3 and 4, and the other configuration is the same as that of the first embodiment. Detailed description of the part is omitted.
The encoder scale unit 5 includes a support member 13, an encoder scale 8, and a contact / separation mechanism.
The support member 13 includes a substantially rectangular sliding portion 13b in which a mountain-shaped support portion 13a is formed on one side surface, and extends from the upper portion of the sliding portion 13b toward the outside in the horizontal direction. And the first L-shaped receiving portion 13c extending upward, and the outer shape of the first receiving portion 13c is bent into a substantially L shape, and is composed of a pair of differently (right hand, left hand). ing. In addition, a long hole 13d having a required length extends from the vicinity of the starting point of the first receiving portion 13c toward the bottom thereof in the sliding portion 13b.

The side plate m to be engaged with the support member 13 is formed in a substantially L shape in which the upper side m1 and the lower side m2 are connected by the vertical side m3, and extends upward from the upper side m1. Is formed to be folded back outward in the horizontal direction so as to be shorter than the first receiving portion 13c. Further, the side plate m has a pivotal support portion m7 in which the upper portion of the rear vertical side m6 facing the vertical side m3 is extended outward in the horizontal direction and its tip is folded back inward of the side plate. Is formed.
The above-described support member 13 has the first receiving portion 13c positioned immediately below the second receiving portion m5, and the back surface of the sliding portion 13b is brought into contact with the outer surfaces of the pair of side plates m (machine frame). In addition, the mountain-shaped support portions 13a are arranged to face each other so as to protrude in the horizontal direction from the vertical side m3 of the side plate m, and a set of two guide pins 10 are connected to the side plate through the long holes 13d. A pair of support members 13 are slidable in the vertical direction with respect to the side plate m.
Furthermore, one end is hooked on the second receiving portion m5, the other end is hooked on the first receiving portion 13c, and the tension spring 14 is stretched between the second receiving portion m5 and the first receiving portion 13c. The support member 13 is always urged upward by the tension spring 14.

As described above, the encoder scale 8 is formed in the shape of a strip plate in which the slit holes 8a are arranged side by side, and a pair of support portions are supported at both ends so that the middle portion thereof is loosely inserted into the opening 4a of the encoder sensor 4. It is fixed to the part 13a. As described above, the encoder scale 8 is installed on the side plate m via the support member 13 that is slidable in the vertical direction.
The contact / separation mechanism includes the side plate m, the tension spring 14, the above-described constituent members of the support member 13, and the contact piece 15.
The abutment piece 15 is formed in a substantially L shape that is suspended from the back surface of the open / close door 12 so as to be able to abut on the first receiving portion 13 c, and the ridge portion 15 a is pivotally supported via the support shaft 16. The door 12 is supported by the m7 so as to be opened and closed.

The contact / separation mechanism configured in this manner closes the door 12 so that the contact piece 15 contacts the first receiving portion 13c, and the support member 13 integrated with the first receiving portion 13c is pushed down. Thus, the encoder scale 8 is loosely inserted into the opening 4 a of the encoder sensor 4. At this time, the encoder scale 8 stops without contacting the encoder sensor 4 via the support member 13 due to the arrangement relationship between the pair of two guide pins 10 and the long holes 13d.
On the contrary, by opening the open / close door 12, the first receiving portion 13c is pulled up while being in contact with the contact piece 15 by the tension spring 14, and the support member 13 integrated with the first receiving portion 13c is pulled up. The encoder scale 8 is separated from the opening 4a of the encoder sensor 4. When the open / close door 12 is fully opened, the contact piece 15 is separated from the first receiving portion 13c so that a sufficient opening is obtained. On the other hand, the encoder scale 8 has two sets of guides. Due to the arrangement relationship between the pin 10 and the long hole 13d, the pin 10 stops at a predetermined position via the support member 13.
The image forming apparatus M according to the second embodiment configured as described above opens the open / close door 12 when replacing the ink cartridge or removing the recording material P due to a paper jam, as described above. The first receiving portion 13c is pulled up while coming into contact with the contact piece 15 by the tension spring 14, and the support member 13 integrated with the first receiving portion 13c is pulled up, and the encoder scale 8 is opened from the opening 4a of the encoder sensor 4. Are separated.

If such a state is ensured, the desired operation described above is performed.
When the desired operation is completed, the door 12 is closed, and as described above, the contact piece 15 contacts the first receiving portion 13c, and the support member 13 integrated with the first receiving portion 13c is pushed down. The encoder scale 8 is loosely inserted and stopped without contacting the opening 4a of the encoder sensor 4.
As described above, in the image forming apparatus M according to the second embodiment, the encoder scale 8 is mounted on the machine frame so as to be able to come in contact with and away from the encoder sensor 4, and the user puts his / her hand inside the apparatus to perform the work. In addition, since the encoder scale 8 can be separated from the encoder sensor 4, the encoder scale 8 that may be accidentally touched during the work can be moved to a safe position before the work can be performed. .
In addition, since the space around the encoder scale 8 is not occupied and the location where the encoder scale 8 is installed is not limited, a layout capable of highly accurate position measurement can be achieved.

In the image forming apparatus M according to the second embodiment, the encoder scale 8 approaches the encoder sensor 4 according to the closed state of the open / close door 12, and the encoder scale 8 is connected to the encoder sensor according to the open state of the open / close door 12. Since the contact / separation mechanism separated from 4 is provided to eliminate the necessity of consciously performing the contact / separation operation of the encoder scale 8, the contact / separation of the encoder scale 8 is performed reliably, greatly improving operability and convenience. It can be improved.
Although the image forming apparatus M according to the present embodiment has been described above, the above-described embodiment shows an example of a preferred embodiment of the present invention, and the present invention is not limited thereto. Various modifications can be made without departing from the scope of the invention.

1 is a partially cutaway perspective view of an image forming apparatus according to a first embodiment. FIG. 2 is a perspective view of a main part in a state where an encoder scale of the image forming apparatus according to the first embodiment is separated from an encoder sensor. FIG. 6 is a perspective view of a main part of an image forming apparatus according to a second embodiment. FIG. 10 is a perspective view of a main part in a state where an encoder scale of an image forming apparatus according to a second embodiment is separated from an encoder sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Carriage, 2 Timing belt, 3 Guide shaft, 4 Encoder sensor, 4a Opening part, 5 Encoder scale part, 6 Exterior cover, 7, 13 Support member, 7a, 13a Support part, 7b, 13b Sliding part, 7c Connection part 7d ear part, 7e 13d long hole, 13c first receiving part, 8 encoder scale, 8a slit hole, 9 operation lever, 10 guide pin, 11, 16 support shaft, 12 open / close door, 14 tension spring, 15 contact piece 15a edge, M image forming apparatus, m side plate, m1 upper side, m2 lower side, m3, m6 vertical side, m4 convex part, m5 second receiving part, m7 shaft support part, P recording material

Claims (6)

A printing execution unit movable in a width direction orthogonal to the recording material conveyance direction; an encoder sensor attached to the printing execution unit; and an encoder scale having a scale detected by the encoder; An image forming apparatus configured to perform position measurement of the print execution unit based on position information of the scale detected by
An image forming apparatus, wherein the encoder scale is attached to a machine frame so as to be able to contact and separate from the encoder sensor.   The image forming apparatus according to claim 1, further comprising: a support member that is provided on the machine frame so as to be linearly movable, and that supports the encoder scale by fixing both ends of the encoder scale.   An operation lever having a midway part pivotally supported by the machine frame and one end engaged with the support member is configured such that the encoder scale can be separated from the encoder sensor by pushing the other end of the operation lever. The image forming apparatus according to claim 2, wherein the image forming apparatus is an image forming apparatus.   The image forming apparatus according to claim 1, further comprising an exterior cover provided with an opening / closing door, wherein the operation lever is disposed inside the opening / closing door. An exterior cover with an open / close door;
A contact / separation mechanism for moving the encoder scale close to the encoder sensor in response to the closed state of the door and for separating the encoder scale from the encoder sensor in response to the open state of the door; The image forming apparatus according to claim 1, wherein:   The image forming apparatus according to claim 1, wherein the print execution unit is a carriage equipped with a droplet discharge head for forming an image by discharging droplets onto the recording material. apparatus.

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