JP2002107943A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recorder, the drum of which is rotatable with a small torque when the position of the center of gravity is adjusted. SOLUTION: Counter weights 32 are disposed in an annular guide groove 31 formed on the side face of the drum 11. A friction scarcely rakes place between the counter weights 32 and the inner face of the guide groove 31 when the counter weights are not fixed with a fixing tool. In order to move the counter weights 32, the drum 11 is rotated so that the position to which the counter weight 32 is moved comes to the lowest position of the guide groove 31, then the fixing tool is pulled out of the guide groove 31. The counter weight moves by gravity to the position of destination. Thus, a correction of balance of the drum 11 of the image recorder is realized with a simple mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus for recording an image by irradiating or selectively heating a photosensitive material such as a plate mounted on a drum with a light beam. The present invention is applicable not only to an image recording apparatus that performs image recording on a photosensitive material using a photocuring action or the like, but also to an image recording apparatus that performs image recording on a photosensitive material using an ablation action. Is also applicable.

[0002]

2. Description of the Related Art Such an image recording apparatus has a cylindrical drum for mounting a photosensitive material on an outer peripheral surface thereof, and a rotary drive for rotating the drum about a rotary shaft provided at the axis thereof. A recording head for irradiating a light beam modulated according to the image signal; In such an image recording apparatus, the recording head irradiates the photosensitive material mounted on the outer peripheral surface of the drum with a light beam while rotating the drum at a high speed, and moves the recording head in a direction parallel to the rotation axis of the drum. By moving, a desired image is recorded on the photosensitive material.

In such an image recording apparatus, photosensitive materials of various sizes are mounted on a drum. Further, in such an image recording apparatus, the photosensitive material is mounted on the outer peripheral surface of the drum by fixing both ends of the photosensitive material to the outer periphery of the drum using a clamp mechanism. The arrangement is changed according to the size of the photosensitive material. For this reason, the position of the center of gravity of the drum after the photosensitive material is mounted differs depending on the size of the photosensitive material mounted on the outer peripheral surface of the drum.

On the other hand, in order to record an image at high speed, it is necessary to rotate the drum itself at high speed. At this time, if the position of the center of gravity of the drum after the photosensitive material is mounted is not located near the rotation axis, forced vibration occurs in the drum during high-speed rotation, and an image may not be recorded with high accuracy. .

[0005] For this reason, Japanese Patent No. 2979750 discloses that
2. Description of the Related Art There has been proposed an image recording apparatus provided with a counterweight composed of a plurality of permanent magnets which can be fixed along a circumference around a rotation axis of a drum and can be moved with a predetermined frictional force. According to the image recording apparatus described in Japanese Patent No. 2977550, by adjusting the positions of a plurality of counterweights, the center of gravity of the drum after the photosensitive material is mounted can be adjusted.
Regardless of the size of the photosensitive material mounted on the outer peripheral surface of the drum, the photosensitive material can be disposed near the rotation axis of the drum, and the drum can be rotated at high speed without generating vibration.

[0006]

However, the image recording apparatus described in Japanese Patent No. 2979750 has a structure in which a predetermined frictional force is generated when the counterweight is moved relative to the drum by a magnetic force. Therefore, there is a problem that a large torque is required when the counterweight moves.

That is, as in an image recording apparatus described in Japanese Patent No. 2997750, for example, a structure is employed in which a counterweight is mounted on a drum with a predetermined frictional force by utilizing a magnetic force or other frictional mechanism. In such a case, a large torque is required when the counterweight is moved with respect to the drum in order to adjust the position of the center of gravity. Therefore, a large torque is applied to the drum as a rotation drive mechanism for rotating the drum. Must be adopted. On the other hand, at the time of recording an image, it is necessary to rotate the drum at a high speed. Therefore, a rotary drive mechanism that satisfies such conditions has a complicated mechanism and a high manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide an image recording apparatus capable of moving a counterweight with a small torque when adjusting the position of the center of gravity.

[0009]

According to a first aspect of the present invention, there is provided an image recording apparatus for recording an image on a photosensitive material mounted on a drum, wherein the photosensitive material is mounted on an outer peripheral surface thereof. A cylindrical drum, a rotary drive mechanism for rotating the drum about its axis, a guide member for guiding a counterweight in a circumferential direction around the axis of the drum with low friction, and A fixing member for fixing a weight at an arbitrary position in the guide member, and acquiring data relating to an adjustment position of the counterweight required to correct the balance of the drum, the drum rotating means and the fixing member And control means for controlling according to the data regarding the adjustment position of the counterweight, and
The control means releases the fixation of the counterweight by the fixing member, and then controls the drum rotating means so that the position at which the vertical line lowered from the axis and the guide member intersect is the fishing line. The image recording apparatus is characterized in that the drum is rotated until it matches the weight adjustment position, and then the fixing member is controlled to fix the counterweight to the guide member.

According to a second aspect of the present invention, in the image recording apparatus of the first aspect, the guide member is a guide groove formed on an end face of the drum, and the counterweight is provided in the guide groove. A spherical weight disposed, wherein the fixing member is
An image recording apparatus comprising: an elastic member; and a moving unit that fits the elastic member between the guide groove and the counterweight surface.

According to a third aspect of the present invention, in the image recording apparatus of the second aspect, the moving means is disposed so as to face a drum end surface at a position where a perpendicular line lowered from the axis and the guide member intersect. An image recording apparatus is provided.

According to a fourth aspect of the present invention, in the image recording apparatus of the first aspect, the guide member is a guide groove formed in an end face of the drum, and the counterweight has a magnetic force of a desired polarity. The fixing member includes magnetic force generating means disposed at a position close to the guide member, and adjusts the intensity of the magnetic force generated by the magnetic force generating means or changes its polarity. Wherein the counterweight is fixed or released.

According to a fifth aspect of the present invention, in the image recording apparatus according to any one of the first to fourth aspects, the control means performs a calculation based on the size of the photosensitive material mounted on the drum. An image recording apparatus for acquiring data relating to an adjustment position of the counterweight necessary for correcting the balance of the drum.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an outline of an image recording apparatus to which the present invention is applied, with a part thereof disassembled, and FIG. 2 is a schematic front view thereof.

This image recording apparatus has a cylindrical drum 11
, A recording head 12, a punch unit 13, a photosensitive material supply unit 14, and an electrical unit 15.

The drum 11 has a photosensitive material 10 on its outer peripheral surface.
A front end clamp 21 for fixing the front end of the photosensitive material 10, a rear end clamp 22 for fixing the rear end of the photosensitive material 10, and a photosensitive material 10.
And a suction hole (not shown) for sucking the back surface of the camera.
The tip clamp 21 rotates between a position where the tip of the photosensitive material 10 is fixed and a position where the tip of the photosensitive material 10 is opened by rotating around the shaft 23 (see FIG. 2) by the action of the tip clamp opening / closing mechanism 24. Further, the rear end clamp 22 is located at a position where the rear end of the photosensitive material 10 is fixed on the surface of the drum 11 and at a position where the rear end is opened away from the drum 11 by the action of the rear end clamp opening / closing mechanism 25. To move between.

The drum 11 includes a rotation drive mechanism 16 described later.
Of the rotary shaft 26 disposed on the shaft
Rotate around. Guide grooves 31 are formed on both ends of the drum 11 along a circumference around the rotation axis of the drum 11, that is, the center axis of the rotation shaft 26, and a pair of fishing grooves are formed in the guide grooves 31. The weight 32 is movably arranged. The configurations of the guide groove 31 and the counterweight 32 will be described later in detail.

The recording head 12 includes a plurality of light emitting elements (not shown). The recording head 12 irradiates a photosensitive material 10 mounted on an outer peripheral surface of a drum 11 with a light beam modulated in accordance with an image signal. This is for forming an image on the material 10. The recording head 12 is fixed on a moving table 38. The moving table 38 is provided with a feed screw 37 which is rotated by driving a motor 36.
Is screwed. For this reason, the recording head 12 is configured to reciprocate in a direction parallel to the rotating shaft 26 of the drum 11 by driving the motor 36.

The punch unit 13 is for punching a positioning punch hole in the photosensitive material 10 before being mounted on the outer peripheral surface of the drum 11, and includes a pair of left and right punches 35.

The photosensitive material supply unit 14 includes an upper tray 33 and a lower tray 34. Unused photosensitive material 1
0 is placed on the lower tray 34. Lower tray 34
The photosensitive material 10 placed on the upper side is once conveyed to the punch unit 13, a punching hole for positioning is formed at the tip, and then placed on the lower tray 34 again.
The photosensitive material 10 is conveyed to the drum 11 from above the lower tray 34, is mounted on the outer peripheral surface of the drum 11, records an image, and is discharged onto the upper tray 33.

FIG. 3 shows the drum 11 as the drum 1 described above.
FIG. 3 is a side view showing a rotation driving mechanism 16 for driving the rotation of the motor 1 and a moving mechanism 17 for moving the above-described counterweight 32 along a guide groove 31;

The rotary drive mechanism 16 for rotating the drum 11 includes a pulley 41 fixed to the rotary shaft 26 of the drum 11 supported by a bearing 39 and a pulley 41.
And a motor 44 connected via a belt 42 and a pulley 43. A rotary encoder 45 is provided on the rotary shaft 26 of the drum 11, and the rotational angle position of the drum 11 is constantly monitored by the rotary encoder 45.

The motor 44 and the rotary encoder 45 in the rotary drive mechanism 16 are connected to a control unit 46. The control unit 46 is connected to an input unit 47 including an input device such as a keyboard. Further, the control unit 4
6 is also connected to the moving mechanism 17 for moving the counterweight 32 along the guide groove 31.

The moving mechanism 17 is for detecting the position of the pair of left and right engaging portions 100 arranged at positions facing the counterweights 32 provided on both end faces of the drum 11 and the position of the counterweight 32. Sensor 40 is provided. The engaging portion 100 can be advanced and retracted in the axial direction of the drum 11 by a motor (not shown), and can be finely moved in the vertical direction. The moving mechanism 17 is configured such that the tip of the engaging portion 100 is
A point at which an imaginary line lowered in the vertical direction from the rotation axis intersects with the guide groove 31 on the end face of the drum 11
Is called the lowermost point).

FIG. 4 is a view conceptually showing a cross section of the drum 11. As shown in this drawing, one guide groove 31 is formed on each end face of the drum 11 with the rotation axis of the rotation shaft 26 of the drum 11 as a center. Each guide groove 31
Are provided with two spherical counterweights 31 each.
The guide groove 31 is formed such that the width of the opening (length indicated by L1 in FIG. 4) is longer than the diameter of the counterweight 32 (length indicated by L2 in FIG. 4). For this reason,
The counterweight 32 can move freely in the guide groove 31 until it is fixed to a desired position of the guide groove 31 by a fixing tool 50 described later. That is, the counterweight 32 generates only zero or a very small frictional force between the counterweight 32 and the wall surface of the guide groove 31.

The opening of the guide groove 31 is
Is partially closed. Thereby, the guide groove 31
Is open toward the outside by the length indicated by the length L3 in FIG. Since the length L3 is shorter than the diameter L2 of the counterweight 32, the counterweight 32 falls out of the guide groove 31 even when the counterweight 32 is not fixed to the guide groove 31 by a fixing tool 50 described later. Nothing.

FIG. 5 is a perspective view of the fixing tool 50.
The fixing tool 50 is mainly penetrated so as to be movable in the vertical direction by a fixing tool main body 51 having projections 52 formed on both sides thereof and a guide hole 54 formed in a vertical piece 53 of the fixing tool main body 51. A rotating shaft 55 and two weight fixing rollers 56 attached to the rotating shaft 55
And two springs 57 for urging the rotating shaft 55 downward, and two frame members 58 fixed on the projecting piece 52.
And 2 that are rotatably held one by one in each frame 58.
And a plurality of guide rollers 59.

A part of the weight fixing roller 56 projects below the fixed tool body 51 by an opening 60 formed in the bottom piece 61 of the fixed tool body 51. Further, the fixing tool main body 51 has an engagement hole 62 formed in the bottom piece 61 for engaging with the distal end of the engagement portion 100 of the moving mechanism 17.

FIG. 6 is a vertical sectional view in which a part of the drum 11 is cut by a plane parallel to the rotation axis of the drum 11 in order to explain the positioning and fixing of the counterweight 32 in the guide groove 31. The fixing tool 50 is positioned in the guide groove 31 while being in contact with the upper wall of the guide groove 31 by the guide roller 59 and in contact with the surface of the counterweight 32 by the weight fixing roller 56. As described above, the weight fixing roller 56 attached to the rotating shaft 55
Is biased downward by a spring 57, and this force acts in a direction in which the counterweight 32 projects outward of the guide groove 31. However, since this portion of the guide groove 31 is closed by the ring member 70, the counterweight 32 cannot move any more, and as a result, the counterweight 32
Is fixed at the corner position of the guide groove 31 by the fixing tool 50.

The spring 57 of the fixing tool 50
Has a biasing force such that the counterweight 32 does not move even when the drum 11 is rotated at a high speed for image recording.

When the fixing tool 50 is removed from the guide groove 31, the counterweight 32 can freely move in the guide groove 31. It is the moving mechanism 17 that takes out the fixed tool 50 from the guide groove 31. That is, the engaging portion 100 of the moving mechanism 17 located outside the drum 11 is advanced toward the end face of the drum 11. When the key portion at the tip of the engaging portion 100 coincides with the engaging hole 62 formed in the bottom piece 61 of the fixing tool 50, the key portion is rotated by a minute amount upward to engage the key portion with the engaging hole 62. . In this state, the engaging portion 10
When 0 is retracted, the fixing tool 50 is also retracted together.
Then, when the fixing tool 50 is completely separated from the guide groove 31, the retreat of the engaging portion 100 is stopped.

In order to fix the counterweight 32, the fixing tool 50 is caused to enter the guide groove 31 from the outside of the drum 11 in the reverse procedure.

The two weight fixing rollers 56 of the fixing tool 50 press the counterweight 32 so as to sandwich the top of the counterweight 32 therebetween. Therefore, the two weight fixing rollers 56 of the fixing tool 50 do not allow the counterweight 32 to move in the guide groove 31 direction when entering the guide groove 31. Therefore, the counterweight 32 can be securely and accurately fixed.

FIG. 7 is a flowchart showing the process of adjusting the balance of the drum 11 of the image recording apparatus.

First, an operator inputs attribute information (size, mass, thickness, presence / absence of a punch, etc.) of the photosensitive material 10 to be wound around the drum 11 from the input section 47 (see FIG. 3) (step S1). .

Next, the photosensitive material 10 is sent out from the photosensitive material supply unit 14 toward the drum 11, and the photosensitive material 10
Is fixed by the front end clamp 21 and the rear end by the rear end clamp 22 (step S2). Rear end clamp 2
At this time, 2 is fixed to the peripheral surface of the drum 11 at a position corresponding to the length of the photosensitive material 10 wound around the drum 11.

In the next step S3, positions where a total of four counterweights 32 arranged on both end faces of the drum 11 are to be arranged are calculated. The arrangement position of the counterweight 32 is determined by the attribute information of the photosensitive material 10 input in step S1 and the winding position of the photosensitive material 10 on the drum 11. Note that the control unit does not necessarily need to calculate the arrangement position of the counterweight 32 as an absolute position on the drum 11, but moves the counterweight 32 from the current position of the counterweight 32, that is, sets the counterweight 32 to the current position. May be calculated as the rotation angle of the drum 11 necessary to move the drum 11 to the adjustment position.

The arrangement position of the counterweight 32 on one end surface of the drum 11 is basically the same as the arrangement position of the counterweight on the other end surface. However, this does not apply to the case where the photosensitive material 10 is not centered in the rotation axis direction of the drum 11 or the case where a plurality of photosensitive materials 10 are wound around the drum 11 peripheral surface. In these cases, it is necessary to eliminate not only the imbalance in the plane orthogonal to the rotation axis of the drum 11 but also the imbalance in the rotation axis direction of the drum 11.

In step S3, the control unit 46 refers to the current arrangement position of the counterweight 32 stored in its internal memory, and determines each balance required to eliminate the imbalance of the drum 11. The movement amount of the weight 32 is calculated.

In the next step S4, it is determined whether or not it is necessary to move each counterweight 32 based on the calculation result in step S3. If it is determined that it needs to be moved, the process proceeds to step S5. If it is determined that it is not necessary, the process skips steps S5 to S9 and proceeds to step S10.

In step S5, first, the counterweight 32 to be moved is selected, and the drum 11 is rotated until the selected counterweight 32 is located at the lowest point of the drum 11.

In the next step S6, the moving tool 17 facing the drum end surface to which the counterweight 32 to be moved belongs belongs to the fixing tool 50 from the counterweight 32.
Remove. As a result, the counterweight 32 is
You will be able to move freely in one.

In this state, the rotation of the drum 11 is restarted. The destination of the counterweight 32 to be moved is the drum 1
The drum 11 is rotated until it reaches the lowest point of 1 (step S7). The counterweight 32 to be moved is the drum 1
With the rotation of 1, the guide groove 31 moves by its own weight.

When the counterweight 32 to be moved reaches the weight position calculated in step S3, the rotation of the drum 11 is stopped. Then, the fixed tool 50 temporarily taken out of the drum 11 in step S6 is moved toward the drum 11 by the moving mechanism 17 (step S8). The fixing tool 50 enters the guide groove 31, and fixes the counterweight 32 in the guide groove 31 by the urging force of the spring 57.

In the next step S9, all the counterweights 32
It is determined whether or not the movement has been completed. If the unadjusted counterweight 32 remains, the process returns to step S5 to start moving the unadjusted counterweight 32. On the other hand, when there is no remaining counterweight 32 for which the arrangement position should be adjusted, the process proceeds from step S9 to step S10. In this step, an image is recorded by the recording head 12 (see FIG. 1) while rotating the drum 11 at a high speed.

When the image recording on the photosensitive material 10 currently wound on the drum 11 is completed, the next step S1 is performed.
At 1, it is determined whether or not to continue the work.
If it is determined that continuation is necessary, the process returns to step S1 and waits for the operator to input various information on the photosensitive material 10 to be used next. If it is determined that continuation is unnecessary, the process ends.

In the present embodiment, the moving means 17 for allowing the counterweight 32 to freely move is arranged at the lowest point of the drum 11, but the moving means 17 may be arranged at other positions. . However, in this case, means for moving the fixing tool 50 into the guide groove 31 and fixing the counterweight 32 must be separately arranged at the lowest point of the drum 11.

As described above, in the image recording apparatus according to the first embodiment, when rotating the drum 11 to move the counterweight 32, the counterweight 32 is stopped by the fixing means outside the drum 11. There is no need to let it. Therefore, the drum 11 can be rotated with a small torque. Further, since the counterweight 32 smoothly moves in the guide groove 31, accurate positioning can be performed. In this embodiment, a sphere is used as the counterweight 32, but a disk whose central axis is parallel to the rotation axis of the drum 11 may be used.

(Second Embodiment) Next, a second embodiment of the present invention will be described. This image recording apparatus is different from the image recording apparatus according to the first embodiment in the method of fixing the counterweight 32. FIG. 8 shows a main part of an image recording apparatus according to the second embodiment. The image recording apparatus according to this embodiment moves the counterweights 87, 88 to an arbitrary position of the guide groove 31 formed on the drum end surface by using a magnetic attraction force and a repulsive force.

The opening of the guide groove 31 is partially closed by a ring member 70. On the side wall 81 of the guide groove 31 on the side near the rotary shaft 26 of the drum 11, a magnetic force generating portion 84 for generating an S-pole magnetic field is fixed over the entire circumference of the guide groove 31. On the other hand, the rotating shaft 2 of the drum 11
On the side wall 83 of the guide groove 31 farther from 6, a magnetic force generating portion 85 for generating a magnetic field of the N pole is fixed over the entire circumference of the guide groove 31. The magnetic force generators 84 and 85 can be individually controlled. Power is supplied to the magnetic force generating units 84 and 85 via the rotating shaft 26 of the drum 11.

The guide groove 31 is provided with two counterweights (a first counterweight 87 and a second counterweight 88).

FIG. 9 is a sectional view showing the first counterweight 87 and the second counterweight 88. As shown in FIG. Each of the counterweights 87, 88 has a substantially rectangular parallelepiped counterweight body 89, 90;
0, permanent magnets 93 and 94 embedded in recesses 91 and 92 formed on one surface.

Each of the counterweight bodies 89 and 90 is made of a non-magnetic material such as resin. The permanent magnet 93 of the first counterweight 87 has its N pole exposed outside the counterweight body 89, and the permanent magnet 94 of the second counterweight 90 has the S pole exposed outside the counterweight body 90. So that each is fixed.

The thickness between the bottom surface of the first counterweight body 89 on the side where the permanent magnet 93 is not fixed and the bottom wall of the concave portion 91 is determined by the magnetic force of each permanent magnet 93. The thickness is such that a significant magnetic field is not generated on the bottom surface, and the thickness is such that the magnetic field generated by the magnetic force generating portion (magnetic force generating portion 85) on the side facing the bottom surface does not significantly affect the permanent magnet 93.

Similarly, for the second counterweight 88, the thickness between the bottom surface of the counterweight body 90 on the side where the permanent magnet 94 is not fixed and the bottom wall of the concave portion 92 is the same as the thickness of each permanent magnet 94.
The magnetic force generated by the magnetic force generating portion (magnetic force generating portion 84) on the side opposite to the bottom surface has a thickness such that the magnetic force does not generate a significant magnetic field on the bottom surface of the counterweight body 90.
The thickness is such that it does not significantly affect No. 4.

Next, the operation of adjusting the balance of the drum 11 will be described with reference to FIG. It is assumed that both of the magnetic force generating units 84 and 85 have already generated a magnetic field at the initial stage. Thus, it is assumed that the first and second counterweights 87, 88 are both fixed at desired positions in the guide groove 31.
Steps S1 to S3 are the same as those in the first embodiment (see FIG. 7), and thus description thereof is omitted.

In step S4, the first counterweight 8
7. If it is determined that the position adjustment of both or one of the second counterweights 88 is necessary, the process proceeds to step S5.

In step S5, the magnetic force generator 84 is stopped. As a result, the first counterweight 87 is no longer fixed in the guide groove 31. As a result, the first counterweight 87
It moves by its own weight to the lowest point of the guide groove 31.

In the next step S6, the drum 11 is rotated at a low speed until the position of the counterweight position calculated in step S3 coincides with the lowest point of the guide groove 31. Since the first counterweight 87 is no longer engaged with the side wall 81 of the guide groove 31, the first counterweight 87 moves in the guide groove 31 by its own weight by the low-speed rotation of the drum 11.

When the first counterweight 87 moves to the counterweight arrangement position, the process proceeds to the next step S7, where the magnetic force generator 84
Activate again. The first counterweight 87 is thereby fixed to the side wall 81 of the guide groove 31 again. The moving process of the first counterweight 87 (steps S5 to S7) is performed in the second
It has no effect on the counterweight 88.

In the next steps S8 to S10, the second counterweight 88 is moved.

In step S8, the magnetic force generator 85 is stopped. As a result, the second counterweight 88 is no longer fixed in the guide groove 31 and moves to the lowest point of the guide groove 31 by its own weight.

In the next step S9, the drum 11 is rotated at a low speed until the position of the counterweight calculated in step S3 coincides with the lowest point of the guide groove 31. Since the second counterweight 88 has no longer been engaged with the outer side wall 83 of the guide groove 31, the second counterweight 88 moves in the guide groove 31 by its own weight by the low-speed rotation of the drum 11.

When the second counterweight 88 moves to the counterweight arrangement position, the process proceeds to the next step S10, where the magnetic force generator 8
Operate 5 again. The second counterweight 88 is thereby fixed to the side wall 83 of the guide groove 31 again. In addition, the moving process of the second counterweight 88 (steps S8 to S10)
Has no effect on the first counterweight 87.

Thus, one of the two counterweights 87, 88
After the completion of the position adjustment of the drum 11,
The image recording is performed on the photosensitive material 10 wound around.

As described above, according to the balance adjusting method according to the second embodiment, the balance weight is not fixed by the device outside the drum during the balance adjustment. In this embodiment, since the position of the counterweight is changed by the own weight of the counterweight, the motor for rotating the drum may have a small torque. Also, the second
In this embodiment, since the counterweight is not fixed in the guide groove by mechanical coupling of members, there is an advantage that the number of members can be reduced.

In each of the first and second embodiments, the guide groove formed in the drum is used as the guide member according to the present invention. Other guide members may be used so that the guide member can be fixed along the circumference around the rotation axis. However, when the guide groove as described above is used as the guide member, it is possible to effectively prevent each counterweight from separating from the end face of the drum due to the centrifugal force accompanying the rotation of the drum while having a simple configuration. It becomes possible.

[0068]

According to the first aspect of the present invention, the balance weight is moved by utilizing its own weight, so that when the balance weight is positioned, the balance weight is disposed outside the drum. There is no need to fix the position by the means provided. Therefore, it is possible to rotate the drum with a small torque when adjusting the position of the center of gravity.

According to the second aspect of the present invention, the counterweight is fixed by fitting the elastic member between the counterweight and the guide groove. Can be moved.

According to the third aspect of the present invention, since the moving means is disposed at a position opposed to the lowermost point of the guide member, when the counterweight reaches the lowermost point of the guide member, the fishing means is moved. It is possible to release the fixation of the weight,
The time until the counterweight stops at the lowest point of the drum due to its own weight can be minimized. That is, quick center-of-gravity position adjustment is possible.

According to the fourth aspect of the present invention, since the counterweight is not fixed by mechanical means, the number of members can be reduced.

According to the fifth aspect of the invention, the position of the center of gravity of the drum can be adjusted only by inputting the size of the photosensitive material mounted on the drum.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an outline of an image recording apparatus to which the present invention is applied, with a part thereof disassembled.

FIG. 2 is a schematic front view of an image recording apparatus to which the present invention is applied.

FIG. 3 shows a rotation drive mechanism 16 for rotating the drum 11 and a fixing tool 50 for rotating the drum 11;
It is a side view shown with the moving mechanism 17 etc. for fitting in.

FIG. 4 is a conceptual vertical sectional view of the drum 11;

5 is a perspective view of the fixing tool 50. FIG.

FIG. 6 shows a guide groove 31 for showing the operation of the fixing tool 50.
It is an expanded sectional view showing an inside.

FIG. 7 is a flowchart for explaining a center-of-gravity adjustment step.

FIG. 8 is an enlarged sectional view showing the inside of a guide groove 31 according to the second embodiment.

FIG. 9 is a vertical sectional view of counterweights 87 and 88 according to the second embodiment.

FIG. 10 is a flowchart for explaining a center-of-gravity adjustment step according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Photosensitive material 11 Drum 12 Recording head 16 Rotation drive mechanism 17 Moving mechanism 26 Rotating shaft 31 Guide groove 32 Counterweight 38 Moving table 39 Axis 40 Sensor 41 Pulley 42 Belt 43 Pulley 44 Motor 45 Rotary encoder 46 Control part 47 Input part Reference Signs List 50 fixing tool 51 fixing tool main body 52 projecting piece 53 vertical piece 54 guide hole 55 rotating shaft 57 spring 58 frame body 60 opening 61 bottom piece 62 engaging hole 70 ring member 81 side wall 83 side wall 84 magnetic force generating section 85 magnetic force generating section 87 first 1 counterweight 88 second counterweight 89 counterweight body 90 counterweight body 91 recess 92 recess 93 permanent magnet 94 permanent magnet 100 engaging portion

Claims (5)

[Claims] 1. An image recording apparatus for recording an image on a photosensitive material mounted on a drum, comprising: a cylindrical drum for mounting the photosensitive material on an outer peripheral surface thereof; A rotation drive mechanism for rotating about the center, a guide member for guiding the counterweight with low friction in a circumferential direction about the axis of the drum, and fixing the counterweight at an arbitrary position in the guide member A fixed member and data relating to the adjustment position of the counterweight required to correct the balance of the drum are obtained, and the drum rotating means and the fixing member are set in accordance with the data relating to the adjustment position of the counterweight. Control means for controlling the rotation of the counterweight, by releasing the fixing of the counterweight by the fixing member, and then controlling the drum rotating means, The drum is rotated until the position where the perpendicular line lowered from the axis and the guide member intersects with the counterweight adjustment position, and then the counterweight is controlled by controlling the fixing member so that the counterweight is transferred to the guide member. An image recording apparatus for performing a process of fixing. 2. The guide member is a guide groove formed in an end face of the drum, the counterweight is a spherical weight disposed in the guide groove, and the fixing member is an elastic member. 2. The image recording apparatus according to claim 1, wherein the image recording apparatus comprises: a moving unit configured to fit the elastic member between the guide groove and the counterweight surface. 3. The image recording apparatus according to claim 2, wherein said moving means is disposed so as to face a drum end surface at a position where a perpendicular line lowered from said axis and said guide member intersect. apparatus. 4. The guide member is a guide groove formed in an end face of the drum, the counterweight includes a magnetic material that emits a magnetic force having a desired polarity to the outside, and the fixing member includes a guide member. A magnetic force generating means disposed at a position close to the member, wherein the strength of the magnetic force generated by the magnetic force generating means is adjusted or its polarity is changed to fix or release the counterweight. The image recording apparatus according to claim 1, wherein: 5. The control means obtains data relating to the adjustment position of the counterweight required to correct the balance of the drum by performing a calculation based on the size of the photosensitive material mounted on the drum. The image recording apparatus according to claim 1, wherein the image recording apparatus is an image recording apparatus.