JPH0124049Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a transfer mechanism of a printing device used for electrophotographic printing and the like.

Among printing devices used in electrophotographic printing, dry printing devices as shown in FIG. 1 are often used.

In the figure, after a photosensitive drum 1 is uniformly charged by a front charging section 2, the photosensitive drum 1 is exposed to light 3 modulated according to an input signal to form an electrostatic latent image. The toner image is developed by the developing section 4, the toner image is transferred onto the paper 5 by the transfer section 6, and the transferred image is fixed by the fixing section 7. On the other hand, residual toner that has not been transferred to the paper 5 on the photosensitive drum 1 is cleaned by the cleaning section 8.

The transfer guide of the transfer section 6 is as shown in FIG.
Two guide members 9 are configured to be rotatable around a fixed shaft 10, and the transfer guides are each connected to one end of a T-shaped metal fitting 11, and the other end of the metal fitting is connected to a pulse motor 12 and an arm 13. They are connected together. The T-shaped fitting 11 is moved along the slide portion 14 by the pulse motor 12, and the two guide members 9 are opened and closed. For example, the paper 5 is pressed against the photosensitive drum 1 at the start of printing as shown in FIG.
Make a movement to pull it away.

The area around the transfer section 6 is structurally susceptible to the effects of toner and paper dust generated by a paper feed tractor (not shown), and these toner and paper dust are transferred to the slide section 14.
There was a problem that the transfer guide could not press the paper 5 against the photosensitive drum 1 or separate it from the photosensitive drum 1 within a certain period of time at the start and end of printing. Also, since the paper 5 is folded along the perforations, if the peaks or valleys of the folds of the paper 5 hit the guide member 9 during printing, there will be no problem if the paper 5 is thin, but if the paper 5 is thick, the resistance will be The holding force of the pulse motor 12 cannot resist the force, and the closed guide member 9 opens, and the paper 5 separates from the photosensitive drum 1. Therefore, it was necessary to increase the holding force of the pulse motor.

An object of the present invention is to solve the above-mentioned problems by providing a link-type transfer mechanism in which the transfer guide drive mechanism is less affected by toner and paper dust.

According to the present invention, a drive mechanism having an output end that approaches and retreats from the pivot shaft of the guide member;
The above object is achieved by providing a pair of link levers at the output end, one end of which is commonly pivoted and the other end of which is connected to the swinging position of the guide member, thereby creating a mechanism for opening and closing the transfer guide. There is.

The present invention will be explained below with reference to examples.

FIG. 3 is a front view showing an embodiment of the transfer mechanism of the printing device according to the present invention.

In the figure, a transfer guide is composed of two guide members 15, and two link levers a and b, which are part of the transfer guide, and another two link levers connected to the two link levers a and b are part of the transfer guide.
A total of four link levers c and d of the book are used as a mechanism to drive the transfer guide, and the guide member connecting portions 16 of the two link levers a and b are fixed to the fixed shaft so that it is in the center of the transfer guide. Attach to the shaft. The link lever coupling portions 17 of the other link levers c and d facing the guide member coupling portion 16 are connected to the arm 18.
It is connected to the shaft of the pulse motor 19 via the motor. Note that the center of the arc formed at the tip of the guide member 15 deviates from the rotation center of the opening and closing of the transfer guide, and the amount of deviation varies depending on when the transfer guide is open, when it is closed, and the path of the paper (paper path). are made to be approximately equal.

Pulse motor 19 when printing is stopped and when printing is finished.
The rotation of the transfer guide releases the transfer guide as shown in FIG.
8 is stopped and positioned, and the paper 5 is separated from the photosensitive drum 1.

At the start of printing and during printing, the rotation of the pulse motor 19 closes the transfer guide as shown in FIG.
Arm 1 with stopper 21 at a distance of about 0.7 mm.
8 is stopped and positioned, and the paper 5 is in contact with the photosensitive drum 1.

As described above, the mechanism that drives the transfer guide is a link type mechanism, and all of the mechanisms rotate, so there is less influence from toner and paper powder, and there is less friction, so the driving torque of the pulse motor 19 is small. I'm done.

Also, when the paper 5 is fed during printing and hits the guide member 15 at the paper folding perforation as shown in FIG. Since the force is received using the connecting portion 16 as a fulcrum, the force received by the link connecting point 22 becomes a component force as shown in the figure. Component force A at the link connection point 22 becomes component force B at the link lever connection part 17, and since this component force B is directed toward the axis of the pulse motor 12, no matter how large it is, it will not affect the holding torque of the pulse motor 19. Since there is no influence and the component force C that has an influence is small, the holding torque can be small.

In the above, the pulse motor 12 is placed below the link lever to reduce the influence of the transfer guide catching on the paper perforations and to reduce the holding torque of the pulse motor. It can also be applied above the lever.
Further, instead of the pulse motor 12, a rotary solenoid, a flange magnet, or the like may be used to drive the connecting portion of the link lever.

The present invention has been described above with reference to embodiments. According to the present invention, the center of the arc formed at the tip of the guide member is shifted from the rotation center of the transfer guide, and the drive mechanism is composed of four link levers, By placing the coupling part of two of the link levers at the center of rotation of the transfer guide, and driving the coupling part of the other link lever facing this to open and close the transfer guide, toner and paper dust can be removed. The effect of being able to provide a transfer mechanism that is less affected by the paper folding perforation and is less affected by catching is significant.

[Brief explanation of drawings]

FIG. 1 is a front view for explaining an example of a conventional printing device, and FIG. 2 is a front view showing the operating state of the transfer mechanism of the transfer unit in FIG. , Fig. 3 shows the operating state of the transfer mechanism of the present invention, A is a front view when the printing is resting, B is a front view during printing, and Fig. 4 is an explanation when the transfer guide of the present invention hits a paper perforation. It is a diagram. In the figure, 1 is a photosensitive drum, 5 is paper, 15
1 is a guide member, 16 is a guide member coupling portion, 17 is a link lever coupling portion, 22 is a link coupling point, 18
19 is a pulse motor, and 20 and 21 are stoppers.

Claims (1)

[Scope of Claim for Utility Model Registration] A pair of guide members, each of which has an arcuate tip end facing each other and whose other end is pivoted to a common guide member joint, are rotated in opposite directions. In the transfer guide mechanism of the printing device, the paper guided and fed along the leading edge approaches and retreats from the transfer position at the same time as the leading edge is opened and closed, the pair of guide members a and b in the swing position of
Connect one end of each of the two link levers c and d,
Link the other ends of the two link levers c and d.
A link mechanism commonly supported by a lever coupling part 17, and a rotational drive source 1 whose one end is rotatably coupled to the link/lever coupling part 17 and whose other end is fixed.
The drive mechanism includes a drive mechanism that causes the guide members a and b to approach and retreat from the transfer position by an arm 18 pivotally supported on a shaft 9, and the guide members a and b cause the paper 5 to approach the transfer position. When the pair of link levers c,
A transfer guide mechanism for a printing device, characterized in that one longitudinal direction of the arm 18 is substantially in line with the longitudinal direction of the arm 18.