JPS6310427B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus that uses a continuous transfer material such as fan-hold paper or roll paper, and particularly relates to an image forming apparatus that uses a continuous transfer material such as fan-hold paper or roll paper, and particularly to The present invention relates to a device for transferring onto another transfer material.

2. Description of the Related Art Conventionally, as image forming apparatuses using continuous transfer materials, recording apparatuses applying various electrophotographic methods have been put into practical use. For example, there is a recording device that performs recording by irradiating a normal electrophotographic photoreceptor with modulated laser light. That is, such a recording device modulates the light intensity of a laser beam using output data from a computer or the like, and uses a scanning means such as a rotating mirror to send the modulated laser beam to a drum-shaped photoreceptor (hereinafter referred to as an information recording element). Exposure is performed by forming an image on the surface of a drum (abbreviated as a drum) and scanning it. The drum undergoes various electrophotographic processes and is exposed to the laser beam described above to obtain an electrostatic potential image. and,
After this image is visualized by development with toner, the visible image is transferred to a transfer material, and further fixed on the transfer material by heating or pressure to perform recording.

The recording apparatus described above does not have a mechanical printing section unlike conventional line printers, so it is capable of high-speed printing, providing a new non-impact printer with high quality and low noise.

Generally, a transfer means for transferring a toner image onto a transfer material is comprised of a corona discharger with excellent transfer efficiency and a guide plate that guides the transfer material along a predetermined path. The corona discharger is installed opposite the drum at the center of the transfer section, and the guide plate is placed at a position such that the transfer paper can come into tangential contact with the drum at the center of the transfer section. Since the distance between the drum surface and the transfer material surface on the guide plate is always maintained constant, the transfer material can run stably, resulting in high transfer efficiency and excellent image quality. . If the distance between the two is inappropriate, the contact between the transfer material and the photosensitive drum will not be stable, resulting in lower transfer efficiency and lower image quality. If there is strong frictional contact, problems may arise in which they may damage each other or damage the transfer material, resulting in interruption of the recording operation. Therefore, it is absolutely necessary to maintain a constant distance between the drum surface and the transfer material surface at all times.

However, the guide plate that guides the transfer material usually has errors in cylindricity and straightness due to manufacturing errors, as well as mechanical accuracy due to non-uniformity of work between manufacturing processes. It is also possible to minimize the above drawbacks by increasing processing accuracy, but this is difficult in practice because it requires advanced processing technology and a significant increase in manufacturing costs. Therefore, there is a need to realize a mechanism that compensates for the defects in the mechanical accuracy of the guide plate without requiring the above-mentioned processing technology or increase in price.

Incidentally, the thickness of a continuous paper transfer material used in an image forming apparatus is usually standardized by a weight expression called ream weight or basis weight. For example, there are six types of transfer materials used in general recording devices, ranging from thin paper with a ream weight of 45 kg to thick paper with a ream weight of 135 kg, and when converted to the metric system, their thicknesses range from 0.068 mm.
Values up to 0.190mm. Even when these sheets of paper are used as a transfer material according to a user's request, it is necessary to maintain the conveyance of the transfer material to the drum in a predetermined contact state so that good image quality can always be obtained. That is, the distance between the surface of the drum and the surface of the transfer material guided by the guide plate is adjusted to the thickness of the transfer material used so that transfer materials of at least six different thicknesses can contact the drum tangentially. A mechanism that changes accordingly is also required.

In addition, in the above-mentioned non-impact printer, during the time from when the device starts recording operation until it stops, that is, while the transfer material is being conveyed to the drum, the transfer material is guided by a guide plate. The transfer material is in contact with the drum surface during transfer, and on the other hand, when the transfer material is not transferring, that is, while the transfer material is stopped, the transfer material must be separated from the drum surface. If you try to perform this kind of operation using a guide plate,
The guide plate is required to have extremely high speed and stable operational response as a condition for forming high quality images.

SUMMARY OF THE INVENTION An object of the present invention is to improve a transfer device that handles a continuous transfer material, and to solve the problem of processing accuracy that the conventional guide means has. Specifically, the purpose is to construct a highly accurate guide means without using particularly high processing precision. Another object of the present invention is to provide a transfer device that allows the use of transfer materials having different thicknesses. The purpose of the above configuration is to improve image quality by always bringing the transfer material into contact with the recording element in a constant state regardless of the thickness of the transfer material.

A transfer device of the present invention that achieves the above object is a transfer device that transfers a toner image formed on a recording element, which is an intermediate recording medium, to a continuous transfer material by corona discharge. a transfer discharge means disposed as a transfer discharge means;
A guide means that constitutes a conveyance path for the transfer material and has a transfer position close to the recording element and a non-transfer position farther from the recording element than the transfer position, and a guide means that is attached to the swinging part of the guide means and that is attached to the swinging part of the guide means. Rotation of the drive source is used to change the position of the guide means from the recording element in order to set the drive source that operates the means, and the position corresponding to the thickness of the transfer material and the position during non-transfer. control means for determining the amount;
The guide means includes a buffer member for absorbing slack in the transfer material when the guide means moves from the transfer position to the non-transfer position.

As an example of the use of the above-mentioned transfer device, it is also possible to set the above-mentioned guide means at a fixed position when starting, and then move it to a predetermined position by detecting the thickness of the transfer material or by inputting from a selection switch. be. By setting the position of the guide means in this way, the user can easily replace and use the transfer material, and the range of application of the recording apparatus can be expanded.

As described above, the transfer device of the present invention includes a guide means for guiding the transfer material to a predetermined position relative to the recording element according to the running and stopping state of the transfer material and the thickness of the transfer material, and a drive means for driving the guide means. By applying a predetermined uniform tension to the transfer material, it is possible to improve the running stability of the transfer material and realize a good transfer state.

Hereinafter, the present invention will be explained in more detail with reference to Examples and explanatory drawings thereof.

FIG. 1 is a schematic cross-sectional view showing the flow of a transfer material and a transfer section of a non-impact printer capable of high-speed operation, and other process mechanism sections of the main body of the apparatus are omitted. In FIG. 1, reference numeral 1 denotes a photosensitive drum which is an information recording element, which is supported by a bearing on a rotating support shaft 2 and rotates in the direction of arrow 3. A unit 4 facing the drum 1 is a transfer device, and has a set of guide plates 5a, 5b and a corona discharger 6 for guiding the transfer material. Reference numerals 7 and 8 indicate tractors for transporting transfer material, and transport a transfer material 9 made of folded continuous paper in the directions of arrows 10 and 11. 1st
In the figure, the transfer material 9 is arranged in the order of a tractor 7, a guide plate 5a, a discharger 6, a guide plate 5b, a tractor 8, and a fixing device 12, and is transported by a tractor or other transport means at a predetermined timing. As is clear from FIG. 1 above, the positional accuracy of the guide plate 5 with respect to the drum 1 is one of the factors that influences the transfer result.

2 and 3 are cross-sectional views schematically showing one embodiment of the present invention, and FIG. 4 is a perspective view of the apparatus shown in FIG. 2, respectively. In the figure, 1 is a drum, 4 is a transfer device, and 5a and 5b (hereinafter also referred to as 5) are guide plates. The guide plate 5 has rotation center shafts 13a, 13b (hereinafter referred to as 13) on one end side.
), and is set at a position close to or remote from the drum 1 by driving the other end side with a drive mechanism to be described later.

The drive mechanism is composed of a drive source and an actuator, and the drive source is a motor 14 such as a pulse motor or a stepping motor that rotates by a certain amount in response to a predetermined signal.
The actuating section is driven by a toothed belt 16 placed over a toothed pulley 15 attached to the rotating shaft of the motor 14. The above-mentioned belt 16 is attached to the operating section on the left side of the figure.
The same toothed pulley 17 that receives the key 1 is attached to the shaft 18.
9 (see Figure 4). That is,
When the pulley 17 rotates, the shaft 18 is driven,
Eccentric cams 21 are fixed to both ends of the shaft 8 by keys 20. A ball bearing 22 such as an ultra-thin ball bearing is connected to the outer periphery of the eccentric cam.
Two eccentric links 23a and 23b (hereinafter also referred to as 23) are attached, and an adjustment link 24 having an elongated hole is attached to the tip of the link 23 with a screw 2.
5a and 25b (hereinafter also referred to as 25). A portion of each guide plate 5 is rotatably attached to the guide plate 5 side of the link 24 via pins 26a and 26b (hereinafter also referred to as 26).

That is, the eccentric link 23 is engaged with the drive shaft 18 via the ball bearing 22 and the eccentric cam 21, and operates each guide plate 5 according to the rotation angle of the drive shaft 18. Further, the driving force to the drive shaft 18 is generated by the drive motor 14, and the driving force to the toothed belt 16 is generated by the drive motor 14.
is transmitted via toothed pulleys 15 and 17.
Further, since the drive motor 14 frequently rotates forward and reverse, it is desirable that the tooth profile of the toothed pulleys 15 and 17 be of a backlashless type. On the other hand, the tip of the guide plate 5, especially in the vicinity of the transfer area, is bent in order to improve the straightness and parallelism of the guide surface of the transfer material, but for this reason, these guide plates 5 tend to be twisted. Mechanical precision is low.

Therefore, when connecting a set of guide plates 5 to the corresponding eccentric links 24 as described above, the torsion of the guide plates is corrected until the drum 1 and the set of guide plates 5 become parallel to each other. By fixing the joint between the adjustment link 24 and the eccentric link 23 with a set screw in the corrected state, the mechanical precision of the guide plate 5 and other members can be improved. Further, near the drive motor 14, a micro switch 27 is fixed to a mounting plate 28 with a set screw. On the other hand, the drive motor 14 is rotated by signals from a drive pulse generation circuit 29 and a drive pulse control circuit 30, and the number of pulses generated by the control circuit 30 determines the forward and reverse drive direction and amount of rotation of the rotating shaft. and the pulse frequency are appropriately selected depending on the thickness of the transfer material and other conditions, and the drive motor 14 is driven by the output of the pulse generation circuit 29. Further, when the drive motor 14 is not in a predetermined position immediately after power is turned on, that is, when the guide plate is not in a fixed and constant state, the switch lever 31 attached to the rotating shaft of the motor 14 switches the micro switch 2.
It is necessary to return the guide plate 5 by rotating the motor to the position where the guide plate 7 is activated. By the way, the micro switch 27 can be replaced by a rotary encoder, a potentiometer, or the like.

In FIGS. 2 and 3, reference numeral 32 denotes a buffer plate which equalizes the tension of the transfer material in the transfer section and prevents it from sagging. Above buffer board 3
2 is rotatably supported on a rotation support shaft 33,
It is urged to rotate counterclockwise by a spring 35 whose one end is attached to a spring hanging shaft 34, and numeral 36 in the figure indicates a stopper that restricts the amount of rotation of the buffer plate 32. Therefore, the buffer plate 32 is
Elastically deformable spring materials such as leaf springs can also be used instead.

On the other hand, numeral 37 near the drum 1 is a peeling plate that guides the transfer material toward the drum 1 and assists in peeling it off from the drum 1 at the same time. In addition, 38 is the peeling plate 3
A rotation support shaft 39 of 7 pulls the release plate clockwise with a spring, and the spring 39 is attached to a spring hanging shaft 41 attached to a fixed plate 40 fixed to a part of the transfer device. Furthermore, a spacer 42 is attached to the end of the peeling plate 37 on the guide plate 5a side, and the peeling plate 37 is pressed by a tension spring 39 via the spacer 42 in the direction of the guide plate 5a. By the way, the gap between the peeling plate 37 and the guide 5a is determined by the thickness of the spacer 42, and by setting the thickness to be the maximum thickness of the transfer material used or slightly larger than that, the peeling effect can be improved and at the same time. Conveyance of the transfer material 9 is not obstructed.

Next, the differences between FIG. 2 and FIG. 3 will be explained below.

In FIG. 2, the transfer material 9 is in a running state, whereas in FIG. 3, it is in a stopped state. In FIG. 2, the drive motor 14 rotates forward by a predetermined number of pulses corresponding to the thickness of the transfer material and then stops. Therefore, the guide plate 5 is disposed close to the drum 1 side so that the transfer material 9 can be brought into contact with the surface of the drum 1 and transferred. Then, in FIG. 3, the drive motor 14 rotates in reverse by a predetermined number of pulses corresponding to the thickness of the transfer material, returns to the position where the micro switch 27 is activated, and then stops. Therefore, the guide plate 5 is connected to the drum 1.
As a result, the transfer material 9 is separated from the surface of the drum 1 and becomes unable to be transferred.

From the above explanation, the guide plate 5 can bring the transfer material into contact with or separate from the drum 1 without moving the entire transfer device, depending on whether the transfer material 9 is running or stopped. has become clear. Next, referring to FIGS. 5 and 6, it will be explained how the guide plate 5 is moved to an optimal position in accordance with the thickness of the transfer material used during transfer.

FIG. 5 shows an example in which a thick transfer material is used, and FIG. 6 shows an example in which a thin transfer material is used. That is, in FIG. 5, the transfer material 9a is paper with a thickness T1, and the upper guide plate 5b is stopped close to the drum 1 at a distance S1, and at this time, the side of the drum 1 of the transfer material 9a is close to the drum 1. 1 and is in a transferable state. On the other hand, in FIG. 6, the transfer material 9b is paper with a thickness T2, and the upper guide plate 5b is stopped close to the drum 1 at a distance S2, similar to the case of the paper 8a in FIG. The drum facing surface of the transfer material 9b is in contact with the surface of the drum 1, and is ready for transfer. Furthermore, during transfer in both FIGS. 5 and 6, when a high voltage is applied to the corona discharger 6 shown in FIGS. 2 and 3, the transfer materials 9a and 9b are electrostatically attracted to the drum 1 side. Contact occurs in area L. Therefore, the transfer material can always be brought into contact with the drum in a constant transfer area regardless of the type of thickness.

As described above, the present invention moves the guide means for guiding the transfer material to a desired position in accordance with the thickness of the transfer material when the transfer material is running or stopped, and at the same time moves the guide means for guiding the transfer material to a desired position relative to the drum. By ensuring the positional accuracy of the guide means and applying appropriate tension to the transfer material as necessary, the transfer material stably travels along a predetermined path and stops, resulting in very stable transfer. This provides a transfer device that enables high image quality and good information recording.

[Brief explanation of the drawing]

Figure 1 is a schematic sectional view of a printer using continuous transfer material, Figures 2 and 3 are sectional views of the transfer device,
Figure 4 is a perspective view of the device in Figure 2, Figures 5 and 6.
The figure is an enlarged view of the transfer section of the transfer device. In the figure, 1 is a photosensitive drum, 4 is a transfer device, 5a, 5b
is a guide plate, 6 is a corona discharger for transfer, 9 is a transfer material, 24a, 24b are adjustment links, 14 is a drive motor, 18 is a drive shaft, 21 is an eccentric cam, 22 is a ball bearing, 23a, 23b are eccentrics 29 is a pulse generation circuit, and 30 is a pulse control circuit.

Claims (1)

[Scope of Claims] 1. In a transfer device that transfers a toner image formed on a recording element, which is an intermediate recording medium, to a continuous transfer material by corona discharge, the device is provided at a transfer position of the recording element and facing the element. A transfer discharge means, which is swingably supported with the side far from the recording element as a fulcrum and forms a transport path for the transfer material, and has a transfer position close to the recording element and a transfer position farther from the recording element than this transfer position. a guide means that assumes a non-transfer position; a drive source that is attached to the swinging portion of the guide means and operates the guide means; and a position that corresponds to the thickness of the transfer material and a position during non-transfer. a control means for determining the amount of rotation of the drive source to change the position of the guide means from the recording element; and a control means for absorbing slack in the transfer material when the guide means moves from the transfer position to the non-transfer position. A transfer device comprising: a buffer member for transferring;