JPH0810380B2 - Contact / separation mechanism of heat roll fixing device - Google Patents

Description

The present invention relates to a contact / separation mechanism of a heat roll fixing device in an electrophotographic recording apparatus.

[Conventional technology]

In the transfer of printing paper having perforations in a conventional electrophotographic recording apparatus, the restoring force of the perforations at the perforations was weakened by the pressure contact force of the heat roll and pressure roll at the time of fixing. The folding was equipped with various folding devices. Further, a skew correction device (roller or the like) is provided for skew correction of the printing paper being conveyed.

[Problems to be Solved by the Invention]

When using the conventional method, in the case of printing paper with perforations, the pressure contact force of the heat roll and pressure roll during fixing weakens the crease possessed by the perforations. The folding operation was hindered. In addition, since a dedicated skew correction means is specially provided for skew correction of the printing paper, the structure is complicated accordingly.

The present invention has been made based on such a situation, and an object thereof is to avoid that the perforation for separating sheets of printing paper is left in contact with a heat roll for a long time. , It is possible to prevent the perforation of the printing paper from being hardened and deteriorated and the crease being weakened due to the overheating crushing action of the heat roll, and skew correction is possible without special skew correction means, which simplifies the configuration. An object is to provide a contact / separation mechanism of a heat roll fixing device.

[Means for solving the problem]

In order to solve the above problems and achieve the object, the present invention takes the following means.

That is, the heat roll 2 rotatably provided,
A pressure roll 3 for press-contacting the printing paper 1 with a perforation 1'for paper division to be heat-fixed to the surface of the heat roll 2, and the pressure roll 3 is rotatably supported at an intermediate portion and at the base end. A support member 5 whose part is rotatably supported, perforation detecting means 18 and 18 'for detecting perforations 1'for separating sheets of the printing paper 1, and perforation detecting means 18 and 18'. When the sheet splitting perforations 1'of the print sheet 1 are detected, the pressure roller 3 is automatically brought into contact with the heat roller 2 by controlling the rotation of the support member 5 based on a detection signal. And means for separating them.

When the pressure roll 3 is separated from the heat roll 2, the support member 5 comes into contact with the heat roll contact surface side of the printing paper 1 at the tip portion thereof, and the printing operation is performed in accordance with the separation operation of the pressure roll 3. Printing paper guide portion 5'for separating the paper 1 from the heat roll 2
Shall be provided.

[Action]

 As a result of taking the above measures, the following effects occur.

(A) When the perforation detecting means 18, 18 'detects the sheet dividing perforations 1'of the printing paper 1, the automatic contact / separation means (lever 10, link plate 8, springs 7, 9, 17 and cam followers). (Including 15 etc.), the supporting member 5 is automatically controlled to rotate, and the pressure roll 3 is automatically separated from the heat roll 2. Along with this separating operation, the printing paper 1 to be heat-fixed, which has been pressed against the surface of the heat roll 2 until then, is printed by the printing paper guide portion 5 ′ provided at the tip of the supporting member 5.
It is pulled in a direction away from the heat roll 2. Therefore, the printing paper 1 is reliably separated from the heat roll 2 together with the pressure roll 3 by a predetermined distance.
As a result, it is possible to avoid that the sheet dividing perforations 1'of the print sheet 1 are left in contact with the heat roll 2 for a long time. Therefore, it is possible to prevent the perforation 1 of the print sheet 1 from being crushed and deteriorated by hardening due to the crushing action of the heat roll 2, and it is possible to prevent the crease, which is the function of the perforation 1 ', from weakening.

(B) Every time the sheet dividing perforation 1'of the print sheet 1 is detected by the perforation detecting means 18, 18 ', the function of the automatic contacting / separating means causes a gap between the pressure roll 3 and the heat roll 2. The contacting / separating operation is repeated. For this reason, the printing paper 1 held by the heat roll 2 and the pressure roll 3 in the sandwiching pressure is intermittently released from the sandwiching pressure holding state at a predetermined time interval. Skew correction of the print sheet 1 is performed by this release operation. Therefore, it is not necessary to provide special skew correction means, and the structure is simplified accordingly.

〔Example〕

Examples of the present invention will be described below. FIG. 1 is a side view showing an embodiment of the present invention, FIG. 2 is a side view showing a state in which a pressure roller is separated from a heat roll, and FIGS. 3 (a) and 3 (b) are pressure contact and separated heat rolls. FIG. 3 is a schematic perspective view showing the relationship between the printing roll and the pressure roll. In the figure, 1 is a printing paper, 2 is a heat roll,
Reference numeral 3 denotes a pressure roll, and both ends of a shaft 4 of the pressure roll 3 are rotatably supported by support members 5.
The support member 5 has one end rotatably supported by the shaft 6,
It is engaged with a protrusion 8 ′ of a link plate 8 pivotally attached to the shaft 6 and is tensioned with each other by a first spring 7. A second spring 9 is provided below the link plate 8 between the link plate 8 and the fixed portion. Further, the tip of the supporting member 5 is a printing paper guide portion 5'having a curved surface of a long arc surface. However, the deviation amount of the link plate 8 biased by the spring 9 is restricted by the stopper 13. Axis 6
Are supported by a frame (not shown), and the support members 5 are biased toward the heat roll 2 by springs 7, respectively, and press the pressure roll 3 against the heat roll 2 with a predetermined pressure contact force. A shaft 11 supported by a frame (not shown) is fitted in the elongated hole portion c of the end portion of the lever 10, and the step portion 10 'of the lever 10 and the end portion of the link plate 8 are engaged with each other. The other end of the lever 10 is connected by a shaft 12 and a cam follower 15 which can rotate about a pivot axis p. A rotatable roller 16 is attached to the end of the cam follower 15 and slides on the surface of the cam 14.
A third spring 17 keeps the roller 16 in pressure contact with the surface of the cam 14. Reference numerals 18 and 18 'are detection means for detecting perforations 1'. When the roller 16 of the cam follower 15 is located at the high position of the cam surface, the cam follower 15, lever 10 and link plate 8
1 is in the state shown in FIG. 1, the pressure roll 3 and the heat roll 2 are in a pressure contact state due to the elasticity of the first spring 7,
When the perforations 1'are detected by the detection means 18, 18 'for detecting the perforations 1', rotation (step) control of a step motor (not shown) for sheet feeding is performed based on the detection signal. Thus, when the perforation 1'reaches near the pressure contact point between the pressure roll 3 and the heat roll 2, the cam 14 is rotated by the step motor, and the roller 16 of the cam follower 15 is positioned at the lower portion of the cam 14.
At this time, the lever 10 moves a predetermined distance in the direction of the arrow shown in the drawing because the cam follower 15 rotates clockwise around the pivot p by the elastic force of the third spring 17, and the step portion 10 ′ of the lever 10 and the link plate 8 are moved. The ends are separated from each other, and thus the link plate 8
Is angularly displaced counterclockwise about the shaft 6 by the elastic force of the second spring 9. However, the deviation amount is regulated by the stopper 13. Further, the protrusion 8 ′ of the link plate 8 pushes down the support member 5, so that the pressure roll 3 is separated from the heat roll 2 by a predetermined distance. At this time, the printing paper 1 is pulled in a direction away from the heat roll 2 by the printing paper guide portion 5'having a long arcuate curved surface that abuts on the contact surface side of the heat roll. It will be separated by a distance. Further, the mounting positions of the detectors 18 and 18 'and the distance to the heat roll 2 and the pressure roll 3 in the present invention are provided at a predetermined distance.

〔The invention's effect〕

 According to the present invention, the following operational effects can be obtained.

(A) When the perforation for detecting the sheet division of the printing paper 1 is detected by the perforation detection means 18, 18 ', automatic contact / separation means (lever 10, link plate 8, springs 7, 9, 17 and cam followers).
(Including 15 etc.), the support member 5 is automatically controlled to rotate, and the pressure roll 3 is automatically separated from the heat roll 2. Along with this separating operation, the printing paper 1 to be heat-fixed, which has been pressed against the surface of the heat roll 2 until then, is printed by the printing paper guide portion 5 ′ provided at the tip of the supporting member 5. It is pulled in a direction away from the heat roll 2. Therefore, the printing paper 1 is reliably separated from the heat roll 2 together with the pressure roll 3 by a predetermined distance. As a result, it is possible to avoid that the sheet dividing perforation of the print sheet 1 is left in contact with the heat roll 2 for a long time. Therefore, it is possible to avoid the deterioration and hardening of the sheet dividing perforations of the print sheet 1 due to the overheating crushing action of the heat rolls 2 and to prevent the crease, which is the function of the perforations, from weakening. And in this case,
Since the print paper guide portion 5'contacts the heat roll contact surface side in the fixed area of the print paper, even if the print surface is rubbed by the guide portion 5 ', print disorder or toner scattering may occur. There is no fear.

(B) Every time the perforation for paper division of the printing paper 1 is detected by the perforation detection means 18, 18 ', the automatic contact / separation means works to bring the pressure roll 3 and the heat roll 2 into contact with each other. The operation is repeated. For this reason, the printing paper 1 held by the heat roll 2 and the pressure roll 3 in the sandwiching pressure is intermittently released from the sandwiching pressure holding state at a predetermined time interval. This release operation causes printing paper 1
Skew correction is performed. Therefore, it is not necessary to provide a special skew correction means separately, and the structure is simplified accordingly.

[Brief description of drawings]

FIG. 1 is a side view showing the principle of the present invention, FIG. 2 is a side view showing the separated state of the pressure roll according to the present invention, and FIGS. 3 (a) and 3 (b) are pressure contact, separated heat roll and pressure. FIG. 3 is a schematic perspective view showing a relationship of printing paper with respect to a roll. 1 ... Printing paper, 1 '... Perforation, 2 ... Heat roll, 3 ... Pressure roll, 5 ... Support member, 6 ...
Shaft, 7 ... spring, 8 ... link plate, 9 ... spring,
10 …… Lever, 11 …… Axis, 13 …… Stopper, 14 …… Cam, 15 …… Cam follower, 16 …… Roller, 17 …… Third spring.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-168183 (JP, A) JP-A-62-92979 (JP, A) JP-A-56-168676 (JP, A) JP-A-56- 109382 (JP, A) JP-A-58-143363 (JP, A) JP-A-1-279279 (JP, A) Actual exploitation Sho-57-116963 (JP, U)

Claims (1)

[Claims] 1. A heat roll rotatably provided, a pressure roll for press-contacting a surface of the heat roll with printing paper having perforations for paper division to be heat-fixed, and the pressure roll at an intermediate portion. A support member that is rotatably supported and has a base end that is rotatably supported, perforation detection means for detecting perforations for sheet division of the printing paper, and the printing paper by the perforation detection means. And a means for automatically contacting and separating the pressure roll with respect to the heat roll by rotationally controlling the supporting member based on a detection signal when the sheet dividing perforation is detected. The member comes into contact with the heat roll contact surface side in the fixed region of the printing paper when the pressure roll is separated from the heat roll at the tip portion. A contact / separation mechanism of a heat roll fixing device, comprising: a print paper guide portion that separates the print paper from the heat roll in accordance with the separation operation of the pressure roll.