JPH02233432A - Form pressing device for printer - Google Patents

Abstract

PURPOSE:To print a form correctly and feed it smoothly regardless of a type of form, whether continuous form or cutform, by providing a change-over member with which pressing force of a paper bail against a platen can be altered in connection with the switch-over movement of a switch-over member. CONSTITUTION:When a printing form is a cutform, a switch-over member 32 is switched over to and positioned at the cutform use position to operate a change-over member 45 and a holding spring 46, in matual association and a platen 2 is pressed strongly by a paper bail 40. Also, when the printing form is a continuous form, the switch-over member 32 is switched-over to and positioned at the continuous form use position and the platen 2 is pressed with lower force than that in the case of cutform by the paper bail 40, in the similar operation.

Description

[Detailed description of the invention]

C. Field of Industrial Application] The present invention relates to a paper holding device for a printer which performs printing by holding printing paper against a platen surface using a paper bail. [Prior Art] In this type of printer, as shown in the partially cutaway side view of the printer in FIG. 11, when printing on the printing paper supplied onto the platen 2, the printing paper does not rise from the printing surface of the platen 2. It is held down by a bar bail 40 as shown in FIG. Therefore, whether continuous paper is printed or cut paper is printed, the paper bail 4o is pressed onto the platen 2 with the same pressing force. [Problems to be Solved by the Invention] However, in the case of unconventional paper, the paper is mainly fed by the bin tractor 14, and the paper bail 40 only serves to pull the paper so that it does not loosen. Generally, the circumferential speed of the platen 2 is set faster than the feed speed of the pin tractor 14, so the platen 2 must be weakly pressed by the paper bail 40 so as not to slip against the printing paper. On the other hand, if the paper bail 40 presses too hard against the platen 2, the paper may be pulled too much.
There was a problem in that the driving boot 17 and the driven boot 18 were painted with negative blue, causing the paper to tear or come off from the bin 19m of the pin tractor 14. Therefore, the pressing force of the paper bail 40 against the platen 2 when feeding continuous paper only needs to be set small. On the other hand, in the case of cut paper, especially small and hard paper such as postcards, there are many requests to print the end of the paper, and if the end of the paper comes off the paper holding roller 5b, the paper is fed only by the paper bail 40. There was a problem that if the pressing force was small, the printed lines would be misaligned. Therefore, the pressing force of the paper bail 40 against the platen 2 is required to be set large. Therefore, in the case of continuous paper, a small pressing force is required, while in the case of cut-sheet paper, a large pressing force is required. There were times when the lines would be misaligned or the paper could not be fed smoothly. The present invention was made in order to solve the above-mentioned problem of delivery time, and it is possible to achieve accurate printing by changing the pressing force of the paper bail against the platen when printing on continuous paper and when printing on cut paper. and for smooth paper feeding. [Means for Solving the Problems] In order to achieve this object, a paper holding device for a printer of the present invention includes a platen rotatably supported between a pair of left and right side walls, and a paper holding device for a printer of the present invention. a paper bail that releasably presses and holds the printing paper;
a holding spring connected at one end to the paper bail so as to urge the paper bail toward a paper holding position on the platen; and a switching member that switches depending on whether the printing paper is continuous paper or cut paper. A conversion member that engages with the other end of the holding spring and converts the pressing force of the paper bail against the platen in conjunction with the switching operation of the switching member.

[Effect]

Therefore, when the printing paper is a cut sheet, by switching the switching member to the cut sheet use position, the converting member and the holding spring are operated in conjunction with each other, and the paper bail presses the platen with a large force. Furthermore, when the printing paper is continuous paper, the switching member is switched to the continuous paper use position, and the same operation is performed so that the paper bail presses the platen with a smaller force than when it is used for cut paper. [Example 1] Hereinafter, an example embodying the present invention will be described in detail with reference to the drawings. As shown in FIG. 3, a platen 2 is rotatably supported by a platen shaft 3 between a pair of side walls 18 of the printer frame 1 and extending along the paper width direction on the paper transport path. Further, a print head 4 that can reciprocate along the platen 2 is arranged in front of the platen 2, and the platen 2, print head 4, etc. print desired information on the cut paper P or the continuous paper Q1. A printing section A is configured for this purpose. Further, below the platen 2, a paper guide plate 6 rotatably supporting paper press rollers 5a and 5b is disposed along the platen 2. As shown in FIG. 1.2, in this embodiment, the paper guide plate 6 is provided below the platen 2 through a pair of support bins 7 (only one of which is shown) that protrudes upward from both upper surfaces of the printer frame 1. It is supported so that it can move up and down. That is, the support bin 7 includes a small-diameter tip 7a and a step 7b. Both sides of the paper guide plate 6 are penetrated and supported by the tip 7a of the support bin 7, and are allowed to move up and down within the length range of the tip 7a, while the range of downward movement is restricted by a step 7b. Furthermore, support protrusions 8 are provided on the upper surfaces of both sides of the printer frame 1 on the lower side of the paper guide plate 6 to protrude upward, and the support protrusions 8 are provided with an actuating member 9 that is tilted to move the paper guide plate 6 up and down. is supported. A tension spring 10 is hung on one end of the operating member 9, and the spring force of the tension spring 10 biases the operating member 9 so that its tip 9a pushes up the paper guide plate 6, and the paper pressing roller 5a, 5b is pressed against the platen 2. That is, the paper pressing roller 5a
, 5b are arranged at a first position where they press against the platen 2 with a strong force. Further, a tension spring l is provided below the actuating member 9 to pull the actuating member 9.
An operating shaft 11 is rotatably supported by the operating member 9 for tilting in the opposite direction against the spring force of O. The operating shaft 11 has a semicircular cross section extending between the side walls la. When the actuating member 9 faces the semicircular notch of the actuating shaft 11, it is tilted in the direction of pushing up the paper guide plate 6 by the action of the tension spring 10. and actuating member 9
is pushed up to its circular outer periphery by rotation of the operating shaft 11 and tilted clockwise. Both side walls 1 of the printer frame 1 as shown in Figure 1.3
A paper bail 40 is arranged between the paper bails 8 and 8 for holding and holding the cut sheets P and the continuous sheets Q. As shown in FIG. 1, this paper bail 40 has a pair of left and right arms 4.
9 (only one of which is shown) is rotatably supported at its lower end by a support bin 41, and a bar 42 extending parallel to the platen 2 is temporarily installed between its free ends, as shown in FIG. A plurality of pressing rollers 43 for pressing the sheets P and Q on the platen 2 are attached to the bar 42, and the pressing rollers 43 and the bar 42 are arranged at an upper position where they do not obstruct the movement of the print head 4. ing. One end of a retaining spring 46 is hung on the bar 42 . Further, below the paper guide plate 6, a pair of thin pressure switching plates 45 are rotatably supported by pins 47. One end of this pressure switching plate 45 engages with the other end of the holding spring 46 through an engaging portion 48, and the lower surface 45a of the other end is brought into contact with the operating shaft 11 by the biasing force of the holding spring 46. As shown in FIG. 2, when the actuating shaft 11 is rotated clockwise, the actuating member 9 is tilted in the same direction around the support protrusion 8 as shown by the two-dot chain line in the figure. Accordingly, the push-up of the paper inner plate 6 by the tip 9a is released, and the paper pressing rollers 5a and 5b are separated from the platen 2. That is, the paper press roller 5m. 5b is arranged at a second position spaced apart from the platen 2. Similarly, the pressure switching plate 45 is also moved downward as shown by the two-dot chain line in FIG. 2 as the actuating member 9 is tilted, and its movement is restricted by a one-step difference 45b. The movement at this time will be explained using vectors according to FIG. Figure 4 shows the retaining spring 46.
The biasing force is expressed as a vector, and this force is divided into the direction of the support bin 41 (X direction in the figure) and the direction of the center of the platen 2 (Y direction in the figure) using the locking bin 44 as a fulcrum. M in the figure indicates when the pressure switching plate 45 is placed in the position shown by the solid line in FIG. Location, that is! 4I2 positions are shown. In the figure, the vector M and the vector N are equal in magnitude, and the operating shaft 11 rotates and the pressure switching plate 45
When moves from the first position to the second position, the ratio of the magnitude of the component force MY in the Y direction of the vector M to the magnitude of the component force NY in the Y direction of the vector N is IMYI/INY
Iζ1.57. That is, when the operating shaft 11 is rotated clockwise and the pressure switching plate 45 is moved to the second position, the engagement portion 48 between the holding spring 46 and the pressure switching plate 45 moves toward the platen 2, and Accordingly, the component force of the holding spring 46 in the Y direction increases. That is, the pressing force of the paper bail 40 against the platen 2 changes by about 1.5 to 7 times. In this embodiment, the cut sheet P supported by the platen 2 and the paper pressing roller 5 is transferred based on the rotation of the platen 2. Furthermore, in this example, as shown in Figure 1.3,
On the upstream side of the platen 2 on the transport path of the paper Q, there is a
A pair of bin tractors 14 (only one shown) is provided. This pin tractor 14 has a well-known structure in which a driving bobbin 17 is provided on a transmission shaft 15 and a guide shaft 16, and a pin belt 19 is hung around a driven bobbly 18.As shown in FIG. Continuous paper Q is fed with feed hole Qa of continuous paper Q being engaged with 19a. Next, the drive mechanism for the platen 2 and the bin tractor 14, and the switching mechanism between continuous sheet feeding and cut sheet feeding will be explained with reference to FIG. 3 and FIGS. 5 to 10. On the outside of one wall 1a of the printer frame 1, a platen gear 21 is fixed to one end of the platen shaft 3, and a transmission shaft gear 22 is similarly fixed to one end of the transmission shaft 15. In the vicinity of the platen gear 21, a two-stage gear 23 consisting of a small-diameter gear portion 23a and a large-diameter gear portion 23b, which are integrally rotatable, is rotatably supported on the side wall 1a via a support shaft 24. A platen gear 21 is meshed with the platen gear 21 . Further, as shown in FIG. 3, a drive motor 25 is attached to the inside of the side wall 1a, and its motor gear 26 is meshed with the large diameter gear portion 23b. Both gears 23 are provided between the two-stage gear 23 and the transmission shaft gear 22.
．． Clutch gear 2 that can connect and disconnect power transmission between
7 are arranged. That is, the third. As shown in Fig. 5.9, a clutch gear 27 is supported on a support shaft 28 fixed to the outside of the side wall 1a so as to be rotatable and capable of reciprocating in the axial direction. Clasp 2 at the tip of the support shaft 28
A compression spring 30 is interposed between the clutch gear 27 and the clutch gear 27, and the clutch gear 27 is engaged with the small diameter gear portion 23a of the two-stage gear 23 and the transmission shaft gear 22, respectively. biased into position. That is,
As a result, a state is set in which the power of the drive motor 25 is transmitted to both the platen 2 and the bin tractor 14. On the other hand, as shown in FIG. 9, the clutch gear 27 is moved to an inactive position away from the side Qla against the spring force of the compression spring 30, so that the clutch gear 27 is engaged with the small diameter gear portion 23a. A state is set in which the drive motor 25 is separated from the transmission shaft gear 22 while holding the position, and the power of the drive motor 25 is transmitted only to the platen 2. Further, as shown in FIG. 7.8, an operating shaft gear 31 is fixedly attached to one end of the operating shaft 11 below the two-stage gear 23. Further, a switching lever 32 as a switching member is provided at one end of the platen shaft 3 in order to perform a switching operation depending on whether the paper is a cut sheet or a continuous sheet. The switching lever 32 is in the continuous paper use position where the operation part 32a is tilted to the right as shown by the solid line in FIG.
It is possible to switch between two different positions, including the position where the paper sheet is used, which is tilted to the left. That is, the switching lever 32 is located at one end of the platen shaft 3 (
Ill! It is rotatably mounted on the platen shaft 3 between the lm and the platen gear 21. As shown in FIGS. 5 to 8, the switching lever 32 has an upper operating section 32m, a lower operating section 32b, and a clutch gear 27.
It consists of an arm portion 32c extending radially outward toward. Further, as shown in FIG. 8, an arcuate gear portion 32d that meshes with the operating shaft gear 31 is formed inside the operating portion 32b. Furthermore, as shown in FIG. 5.7.8, a clutch gear 27 is provided at the tip of the arm portion 32c.
An engaging portion 32e that can be engaged with one side surface is provided to protrude downward, and an engaging slope 32f is formed on the surface facing the compression spring 30. In addition, in this embodiment, as shown in FIGS. 6 to 8, the side walls 1a
On the outside, there is a switching lever 32 that can output signals corresponding to the usage status of the cut paper P and the continuous paper Q, respectively.
A removable changeover switch 33 is provided on a part of the operating portion 32b to detect the switching position of the switch. Based on this switching of the changeover switch 33, when continuous paper is in use, a control section (not shown) controls the drive motor 25.
A program corresponding to the continuous paper Q is executed as a program for controlling the rotation of the continuous paper Q, and the printer displays characters or symbols indicating the use status of the continuous paper Q on the display section 36 on the panel switch 35 shown in FIG. For example rFORMs
J is displayed. On the other hand, when the cut sheet is in use, the program corresponding to the cut sheet P is executed, and at the same time, the printer displays characters or symbols indicating the use state of the cut sheet P, such as rsHEETJ, on the display section 36. Ru. When the operating portion 32m of the switching lever 32 is placed in the continuous paper use position as shown by the solid line in FIG. 23, the clutch gear 27 and the transmission shaft gear 22 enter the power transmission state. Also, based on the meshing between the gear portion 32d on the side of the action portion 32b and the actuation shaft gear 31, the actuation shaft 1
1 tilts the actuating member 9 as shown in FIG. 2, and holds each paper pressing roller 5 together with the paper guide plate 6 in a state separated from the platen 2. At this time, the pressure switching plate 45
is the operating shaft 1 at the step 45b as shown in FIG.
It is in a state where it is supported by 1. By operating the drive motor 25 in this state, the platen 2 is rotated via the motor gear 26, the second gear 23, and the gear 21, and at the same time, the small diameter gear portion 23a
The transmission shaft 15 is rotated via the first clutch gear 27 and the transmission shaft gear 22, and the bin belt 19 is moved around. This allows the continuous paper Q to be fed. Since the pressure switching plate 45 is in the above-described position, the pressing force of the paper bail 40 against the platen 2 is smaller than that when pressing a cut sheet, which will be described later. On the other hand, when the operating portion 32a of the switching lever 32 is placed in the slip paper use position as shown by the two-dot chain line in FIG.
7 is pushed against the compression spring 30, the gear 27 is disengaged from the transmission shaft gear 22, and power transmission to the transmission shaft 15 is cut off. Therefore, based on the operation of the drive motor 15, the platen 2
only is rotated. Further, as the switching lever 32 is switched, the operating shaft 11 allows the operating member 9 to be tilted by the tension spring 10 as shown in FIG. is maintained in the same state. At this time, the operating shaft 11 is rotated counterclockwise in FIG. IN2, and the pressure switching plate 45 moves from the position shown in FIG. 2 to the position shown in FIG. 1. At this time, the pressing force of the paper bail 40 against the platen 2 is approximately 1.57 times as shown by the vector in FIG. You will have to press Therefore, even if the paper sheet P is small and hard like a postcard, the paper bail 40 presses the platen 2 with a strong force, so that printing lines can be accurately printed without shifting. As described above, in the paper feeding device of this embodiment, by operating only one switching lever 32, the switching arrangement of the paper pressing roller 5 for single sheet feeding or continuous sheet feeding, and the power transmission to the platen 2 and the bin tractor 14 can be changed. It is possible to change the settings and also to change the settings of the signal output from the changeover switch 33 corresponding to single sheet feeding or continuous sheet feeding in association with each other and to perform them at the same time. In addition, by operating the switching lever 32, the paper bail 4
Since the pressure applied to the platen 2 is set to be changed, the paper can be fed with an appropriate pressure for each. Note that this invention is not limited to the above embodiments,
The present invention can be implemented as follows by changing a part of the structure as appropriate without departing from the spirit of the invention. (1) In the above embodiment, the paper pressing roller 5 is switched between the first position where it presses against the platen 2 with a strong force and the second position where it is separated from the platen 2. The first position where pressure is applied and the platen 2
It is also possible to provide a second position that is pressed against with a weak force. That is, when performing continuous paper feeding, the paper pressing roller 5 may be in contact with the continuous paper Q. (2) In the embodiment described above, the bin tractor 14 was provided on the upstream side of the platen 2, but the bin tractor 14 may be provided on the downstream side of the platen 2, or on both the upstream and downstream sides. [Effects of the Invention] As detailed above, according to the present invention, the pressing force of the paper bail against the platen is set to be changed by switching the switching lever depending on whether the printing paper is continuous paper or cut paper. Therefore, it is possible to perform accurate printing and smooth paper feeding, whether it is continuous paper or cut paper.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway side view of the printer when paper is being fed.
Figure 2 is a partially cutaway side view of the printer during continuous paper feeding.
Figure 3 is a partially cutaway plan view of the printer, Figure 4 is a vector representation of the pressure force of the paper bail on the platen, and Figure 5 is a partially cutaway diagram showing the installation state of each gear, switching lever, etc. A perspective view, FIG. 6 is a partially exploded perspective view showing how each gear is installed, FIG. 7 is a side view showing how each gear and switching lever are installed, and FIG. 8 is a switching lever. FIG. 9 is a partially cutaway side view illustrating the relationship between the clutch gear and the changeover switch; FIG. 9 is a partially cutaway side view illustrating the action of the clutch gear; FIG. 10 is a perspective view showing the entire printer; The figure is a partially cutaway side view of a conventional printer. In the figure, 2 is a platen, 32 is a switching lever, 40 is a paper bail, 45 is a pressure switching plate, and 46 is a holding sublink.

Claims (1)

[Scope of Claims] 1. A platen rotatably supported between a pair of left and right side walls; a paper bail that releasably presses and holds printing paper on the platen above a printing position; and the paper bail. a retaining spring connected at one end to the paper bail so as to bias toward a paper holding position on the platen; a switching member for switching depending on whether the printing paper is continuous paper or cut paper; and the retaining spring. a converting member that engages with the other end and converts the pressing force of the paper bail against the platen in conjunction with the switching operation of the switching member.