Image formation device

Abstract

To provide an image formation device which prevents register sensors from falsely operating without using a high-cost solenoid and shutter even under conditions of no gaps between components near the register sensors.SOLUTION: An image formation device includes: register sensors 13 which are provided opposite to a transfer belt 11 and which detect the density and a position of a pattern image formed on the transfer belt 11; a sensor frame body 14 which supports the register sensors 13 inside and in which detection parts of the register sensors 13 open; and a cleaning rod 17 for cleaning sensor reading surfaces provided at the detection parts of the register sensors 13. The sensor frame body 14 can move in a direction of separating from the transfer belt 11.SELECTED DRAWING: Figure 3B

Description

[Technical field]

[0001] The present disclosure relates to an image forming apparatus. [Background technology]

[0002] Conventionally, in image forming apparatuses, a registration sensor is arranged near a transfer belt to detect toner shift and density on the transfer belt. Image forming apparatuses having such a configuration are disclosed, for example, in Japanese Patent Application Laid-Open No. 2003-195578 ​​(Patent Document 1) and Japanese Patent Application Laid-Open No. 2009-258245 (Patent Document 2). Patent Document 1 discloses an image forming apparatus in which a registration sensor is arranged above a transfer belt, and Patent Document 2 discloses an image forming apparatus in which a registration sensor is arranged opposite a photosensitive drum. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-195578 ​​A [Patent Document 2] JP 2009-258245 A Summary of the Invention [Problem to be solved by the invention]

[0004] The registration sensor of the conventional image forming apparatus was configured as described above. In the registration sensor disclosed in Patent Document 1 and Patent Document 2, a shutter that opens and closes under the control of a drive source such as a solenoid was provided on the reading surface of the registration sensor to prevent the registration sensor from malfunctioning due to the adhesion of toner from the transfer belt to the reading surface of the registration sensor. This resulted in high costs. Therefore, in order to reduce costs, it was considered to eliminate the shutter and instead clean the reading surface of the registration sensor. In addition, due to the miniaturization of the image forming apparatus, there is no gap between the components near the registration sensor, and a registration sensor with a long focal length cannot be used, so there was also a problem that a configuration that can perform cleaning even under such conditions was required.

[0005] The present disclosure has been made to resolve the above-mentioned problems, and aims to provide an image forming device in which the registration sensor does not malfunction, even when there are no gaps between components near the registration sensor, without using a costly shutter. [Means for solving the problem]

[0006] The image forming apparatus according to the present disclosure comprises an optical sensor disposed opposite a transfer belt for detecting the density and position of a pattern image formed on the transfer belt, a sensor frame for supporting the optical sensor internally and having an opening for a detection portion of the optical sensor, and a cleaning member for cleaning the sensor reading surface provided on the detection portion of the optical sensor, and the sensor frame is movable in a direction away from the transfer belt.

[0007] Preferably, the cleaning member is attached to a cleaning rod, the cleaning rod is arranged to extend in a direction perpendicular to the rotational direction of the transfer belt, the cleaning rod is movable in the longitudinal direction of the cleaning rod so as to switch between an abutment state in which the cleaning member abuts against the sensor reading surface and a retracted state in which the cleaning member does not abut against the sensor reading surface, and as the cleaning rod moves from the retracted state to the abutment state, the optical sensor moves in a direction away from the transfer belt.

[0008] More preferably, the sensor frame is arranged to extend in a direction perpendicular to the rotation direction of the transfer belt, the cleaning rod has a convex portion extending downward, and the sensor frame has a groove portion through which the convex portion moves, and the sensor frame moves away from the transfer belt as the convex portion moves in the groove portion.

[0009] According to one embodiment of the present disclosure, the optical sensor is rotatably attached to the sensor frame, the cleaning member is fixed to a cleaner holder provided adjacent to the sensor frame, and the optical sensor may abut against the cleaning member by rotating from a position facing the transfer belt. Effect of the Invention

[0010] According to the present disclosure, the sensor frame that holds the optical sensor can be moved in a direction away from the transfer belt, and the optical sensor is cleaned with a cleaning member in this state. This makes it possible to provide an image forming device in which the registration sensor does not malfunction, even when there are no gaps between the components near the registration sensor, without using a costly shutter.

[0011] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description of the embodiments with reference to the drawings. [Brief description of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing a main configuration of an image forming apparatus according to an embodiment of the present disclosure. [Figure 2A] 4 is a diagram showing the vicinity of a registration sensor in a direction perpendicular to a rotation direction of a transfer belt in the first embodiment of the present disclosure. FIG. [Figure 2B] 2B is a perspective view of the configuration in the vicinity of the registration sensor shown in FIG. 2A, as viewed obliquely from above in a direction perpendicular to the rotation direction of a transfer belt (not shown). FIG. [Figure 3A] 6 is a diagram showing a positional relationship between a cleaning rod near a transfer belt and a registration sensor under normal circumstances in the first embodiment of the present disclosure. FIG. [Figure 3B] 6 is a diagram showing a positional relationship between a cleaning rod near a transfer belt and a registration sensor during cleaning in the first embodiment of the present disclosure. FIG. [Figure 4A] 13 is a diagram showing a positional relationship between a cleaning rod near a transfer belt and a registration sensor under normal circumstances in a second embodiment of the present disclosure. FIG. [Figure 4B] 13 is a diagram showing the positional relationship between a cleaning rod near a transfer belt and a registration sensor during cleaning in a second embodiment of the present disclosure. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a main configuration of an image forming apparatus according to an embodiment of the present disclosure. Referring to FIG. 1, an image forming apparatus 50 includes an apparatus main body 51, an image forming section 52 provided in the apparatus main body 51, a paper conveying system 53 provided on the right side of the image forming section 52, and an image reading device 54 provided on the upper part of the apparatus main body 51. The image forming section 52 includes a transfer belt 11 that passes through four image forming units of Y, M, C, and K and rotates in the direction indicated by the arrow in the figure, and is provided with a registration sensor 13 that detects the density and position of a pattern image formed on the transfer belt 11 immediately before a secondary transfer roller 55 of the transfer belt 11.

[0014] In FIG. 1, the near side is the front side of the image forming apparatus 50, and the far side is the rear side of the image forming apparatus 50.

[0015] [First embodiment] First, a first embodiment of the present disclosure will be described. Fig. 2A is a diagram showing a configuration in the vicinity of a registration sensor in a direction perpendicular to the rotation direction of a transfer belt in the first embodiment of the present disclosure, and is an enlarged view of a portion circled in Fig. 1. Referring to Fig. 2A, a registration sensor 13 for detecting the density and position of a pattern image formed on the transfer belt 11, a sensor frame 14 for supporting the registration sensor 13 internally and having an opening at a detection portion (upper portion of the registration sensor 13) of the registration sensor 13, and a cleaning rod 17 provided between the transfer belt 11 and the registration sensor 13 are shown below the transfer belt 11 facing the transfer belt 11.

[0016] Fig. 2B is a perspective view of components near the registration sensor 13 shown in Fig. 2A, seen from diagonally above in a direction perpendicular to the rotation direction of a transfer belt (not shown). As shown in Fig. 2B, the cleaning rod 17 is composed of two members extending parallel to each other and perpendicular to the rotation direction of a transfer belt (not shown), with the cleaning member 18 and the registration sensor 13 disposed between them, and the cleaning rod 17 not provided in the space above the registration sensor 13. With this configuration, the cleaning member 18 is attached to the cleaning rod 17 and cleans the sensor reading surface provided in the detection section of the registration sensor 13.

[0017] Fig. 3A is a diagram showing the positional relationship between the cleaning rod near the transfer belt and the registration sensor in normal operation (during image formation) in the first embodiment of the present disclosure, and Fig. 3B is a diagram showing the positional relationship between the cleaning rod near the transfer belt and the registration sensor during cleaning in the first embodiment of the present disclosure. In this embodiment, two registration sensors 13 are provided in the width direction of the transfer belt 11.

[0018] 3A and 3B are diagrams showing the arrangement of the transfer belt 11, the registration sensor 13, the sensor frame 14, and the cleaning rod 17 in a direction perpendicular to the transfer belt 11 shown in FIGS. 2A and 2B.

[0019] 3A and 3B, in the first embodiment, in a direction intersecting the rotational direction of transfer belt 11, cleaning rod 17 located below transfer belt 11 is movable in the width direction of transfer belt 11 as indicated by the arrow in the figure.

[0020] Two registration sensors 13 are provided at a fixed interval on the upper part of the sensor frame 14, and two cleaning members 18 are attached to the cleaning rod 17 in accordance with the fixed interval between the two registration sensors 13. In the figure, the left side is the rear side of the image forming apparatus 50 (see FIG. 1), and the right side is the front side.

[0021] First, referring to Fig. 3A, under normal circumstances, cleaning member 18 attached to cleaning rod 17 provided under transfer belt 11 is in a retracted position shifted to the left of registration sensor 13 and does not come into contact with the sensor reading surface, and cleaning member 18 is in a position lower than the upper end of registration sensor 13. To enable such an arrangement, cleaning rod 17 provided on top of registration sensor 13 fixed to the top of sensor frame 14 is composed of two parallel members as described in Fig. 2B.

[0022] In addition, the gap d between the transfer belt 11 and the registration sensor 13 under normal circumstances is only about 4 to 7 mm, and there is no gap between the components in the vicinity of the registration sensor 13.

[0023] As shown in Fig. 3A, the cleaning rod 17 has three arms (convex portions) 20 that protrude downward and are provided at equal intervals across the entire width of the transfer belt 11, and the arms 20 are connected to slits (groove portions) 21 provided in the sensor frame 14 and can move along the slits in the width direction of the transfer belt 11. Here, as shown in Fig. 3A, the slit 21 has a path that is horizontal to the right in the figure, inclined upward, and then horizontal.

[0024] Next, the cleaning operation will be described. Referring to Fig. 3B, during cleaning, the cleaning rod 17 is moved to the right with respect to the transfer belt 11 as shown by the rightward arrow in the figure. Then, the arm 20 moves along the slit 21, and the sensor frame 14 moves downward as shown by the downward arrow in the figure. As a result, the sensor frame 14 moves in a direction away from the transfer belt 11, and the cleaning member 18 comes into contact with the registration sensor 13, bringing the registration sensor 13 into a contact state in which the cleaning member 18 can clean the registration sensor 13, and the cleaning member 18 attached to the cleaning rod 17 cleans the sensor reading surface provided on the detection portion of the registration sensor 13.

[0025] In this manner, by moving the sensor frame 14 downward, the gap d between the transfer belt 11 and the registration sensor 13 increases from the original position indicated by the dotted line in FIG. 3B to the position indicated by the solid line.

[0026] That is, the cleaning rod 17 is provided extending in a direction perpendicular to the rotation direction of the transfer belt 11, and the cleaning rod 17 has a cleaning member 18. The cleaning rod 17 is movable in the longitudinal direction of the cleaning rod 17 (the width direction of the transfer belt 11) so as to be in an abutting state in which the cleaning member 18 abuts against the sensor reading surface of the registration sensor 13, and in a retracted state in which the cleaning member 18 does not abut against the sensor reading surface of the registration sensor 13. When the cleaning rod 17 moves from the retracted state to the abutting state, the registration sensor 13 moves in a direction away from the transfer belt 11.

[0027] In addition, the sensor frame 14 is also extended in a direction perpendicular to the rotation direction of the transfer belt 11, and has a slit 21 through which the arm 20 of the cleaning rod 17 moves, and as the arm 20 of the cleaning rod 17 moves through the slit 21, the sensor frame 14 moves in a direction away from the transfer belt 11.

[0028] [Second embodiment] Next, a second embodiment of the present disclosure will be described. Fig. 4A is a diagram showing the positional relationship between the cleaning rod near the transfer belt and the registration sensor in normal operation in the second embodiment of the present disclosure, and Fig. 4B is a diagram showing the positional relationship between the cleaning rod near the transfer belt and the registration sensor during cleaning in the second embodiment of the present disclosure.

[0029] 4A, in the second embodiment, under normal circumstances, the transfer belt 11 rotates in the direction indicated by the arrow in the figure, and the gap d between the transfer belt 11 and the registration sensor 23 is the same as in the previous embodiment, as shown in the figure. The sensor frame 24 holding the registration sensor 23 and the cleaner holder 25 holding the cleaning member 28 are both rectangular members that are long toward the transfer belt 11 side, and are arranged adjacent to each other with a small gap between them, with the registration sensor 23 and the cleaning member 28 facing the transfer belt 11 side in parallel.

[0030] Here, the cleaning member 28 is disposed with its cleaning surface diagonally downward and to the right, and is fixed to the cleaner holder 25 by a locking member (not shown). The registration sensor 23 detects the printing state including the density and position of the pattern image formed on the transfer belt 11. The registration sensor 23 is attached to the sensor frame 24 while being biased by a spring 27 so as to be rotatable to the left about a fulcrum 26 provided at the lower right position of the sensor frame 24.

[0031] Next, the cleaning operation will be described with reference to Fig. 4B. During cleaning, the registration sensor 23 rotates leftward from a state in which it faces the transfer belt, centering on the fulcrum 26 provided at the lower right position of the sensor frame 24, to come into contact with the cleaning surface of the cleaning member 28, and the sensor reading surface of the detection portion of the registration sensor 23 is cleaned. At this time, the gap d between the transfer belt 11 and the registration sensor 13 is wider than in the normal state shown in Fig. 4A.

[0032] 4A and 4B are views seen from the rotation direction of transfer belt 11, unlike Fig. 3A and Fig. 3B. In this embodiment as well, two registration sensors 23 are provided in the width direction of transfer belt 11, and therefore, the same registration sensor 23 as in Fig. 4A and 4B is also provided in the depth direction of Fig. 4A and Fig. 4B.

[0033] In the above embodiment, the configuration of the locking member (not shown) that locks the cleaner holder 25 that holds the cleaning member 28 is not particularly limited, but the locking member may be configured as follows: That is, under normal circumstances, the locking member that locks the cleaner holder 25 that holds the cleaning member 28 may be linked to, for example, a front door (not shown) of the image forming apparatus 50 (see FIG. 1), and the locking by the locking member may be released by opening and closing the front door, causing the registration sensor 23 to rotate, so that the cleaning member 28 can clean the registration sensor 23.

[0034] In the above embodiment, the two registration sensors 13 and 23 are provided in the width direction of the transfer belt. However, the present invention is not limited to this, and it is sufficient to provide at least one.

[0035] The present disclosure can be implemented in various other forms without departing from its spirit or main features. Therefore, the above-described embodiments are merely illustrative and should not be interpreted as being limited. All modifications and variations within the scope of the claims of the present disclosure are within the scope of the present disclosure. [Industrial Applicability]

[0036] According to the present disclosure, an image forming device can be provided in which the registration sensor does not malfunction, even when there are no gaps between components near the registration sensor, without using costly solenoids and shutters, and thus the image forming device is useful as an image forming device. [Explanation of symbols]

[0037] 11 Transfer belt 13,23 Register sensor (optical sensor) 14,24 Sensor frame 17 Cleaning rod 18,28 Cleaning materials 20 Arm (convex part) 21 Slit (groove) 25 Cleaner holder 26 fulcrum 27 Spring 50 Image forming device 51 Device body 52 Image forming section 53 Paper transport system 54 Image reader 55 Secondary transfer roller

Claims

1. an optical sensor provided opposite the transfer belt for detecting the density and position of a pattern image formed on the transfer belt; a sensor frame that supports the optical sensor therein and has an opening for a detection portion of the optical sensor; a cleaning member that cleans a sensor reading surface provided on the detection portion of the optical sensor, The sensor frame is movable in a direction away from the transfer belt.

2. The cleaning member is attached to a cleaning rod, the cleaning rod is provided extending in a direction perpendicular to a rotation direction of the transfer belt, the cleaning rod is movable in a longitudinal direction of the cleaning rod so as to be in a contact state in which the cleaning member is in contact with the sensor reading surface and in a retracted state in which the cleaning member is not in contact with the sensor reading surface, 2 . The image forming apparatus according to claim 1 , wherein the optical sensor moves in a direction away from the transfer belt as a result of the cleaning rod moving from the retracted state to the contact state.

3. the sensor frame is provided extending in a direction perpendicular to a rotation direction of the transfer belt, The cleaning rod has a protrusion extending downward, the sensor frame has a groove in which the protrusion moves, The image forming apparatus according to claim 2 , wherein the sensor frame is moved away from the transfer belt by the projection moving along the groove.

4. the optical sensor is rotatably attached to the sensor frame; The cleaning member is fixed to a cleaner holder provided adjacent to the sensor frame, The image forming apparatus according to claim 1 , wherein the optical sensor is rotated from a state facing the transfer belt to come into contact with the cleaning member.

Images