JPS61130150A - Cut paper printer - Google Patents

Abstract

PURPOSE:To prevent the occurrence of printing on the back, by a method wherein a surface and back detecting part, discriminating the surface and the back through comparison of the friction conditions of the surface of the back of the paper, is located in a paper feed passage between a cut paper accumulating part and a printing part, and turn-over of the paper is instructed in response to an output signal therefrom. CONSTITUTION:Driving of motors 7 and 10 is controlled by means of a motor control circuit 13, and a rotation peripheral velocity R of a second feed roller 11 is slightly increased compared with a rotation peripheral velocity (r) of a first feed roller 8. Thus, a paper 1a is pulled by means of a second feed mechanism 6, and a friction force is produced between a first feed mechanism 5 and the paper. Rotation detectors, comprising slit discs 14 and 15, light sources 16 and 17, photosensors 18 and 19, are located on the rotation shafts of a feed roller 8 and a pinch roller 9, respectively, by which the friction force is generated. Outputs therefrom are respectively inputted to pulse counters 20 and 21 to count pulses therefrom, the results are compared with each other by a comparing circuit 22 to determine the set state of a paper 1. The result is displayed in a display lamp 23. This enables prevention of printing on the back.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an improvement in a cut paper printer that prints computer output information using cut paper, and in particular to printing by printing a door on the surface of the paper using an electrophotographic method. The present invention relates to a cut paper printer in which a function Wlta for determining the front and back sides of printing paper is added to a device that performs this, thereby preventing printing defects due to incorrect setting of paper.

[Conventional technology]

In order to print computer output information in Japanese format including kana and kanji, many recent office printers employ an electrophotographic method using a laser light source. Such printers typically use printing paper whose surface has been treated to make it smooth in order to ensure that the transferred toner adheres to the paper. However, in conventional printers, even if a cut sheet to be printed is set with the wrong front and back sides, printing continues as is, resulting in poor print quality.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional situation, it is an object of the present invention to provide a new cut paper printer that automatically determines the front and back sides of printing paper and prevents printing on the back side.

[Means for solving problems]

Briefly stated, the cut paper printer according to the present invention utilizes a part of the feeding mechanism in the paper feeding path between the cut paper stacking section and the printing section in order to achieve the above object. + on both sides of the paper! ! This paper is characterized in that it is provided with a front/back detection unit that determines whether the paper is front or back by comparing the rubbing conditions, and instructs to reverse the sheet in response to an output signal from the front/back detection unit.

[Function] That is, the surface of printing paper used in an electrophotographic cut paper printer is smoothed to improve toner adhesion, so it is more slippery than the back surface. Therefore, by detecting such a difference in the frictional state, it is possible to distinguish between the front and back sides.In this invention, a part of the paper feeding path is used to detect the frictional state of the front and back sides of the paper being fed, and the comparison results are I try to point out mistakes in paper cents.

〔Example〕

Preferred embodiments of the present invention will be described in more detail below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a cut paper printer equipped with a front/back detection unit according to the present invention, and includes a paper stacking unit 2 that stores and stores a required amount of cut paper 1, and a block 3 as a representative example. A front/back detection section 4, which is a feature of the present invention, is provided between the printing section and the printing section. The printing section 3 consists of an optical recording section for a charge image (not shown), a developing section using toner, a section for transferring the toner image onto paper, and a fixing section, and is not particularly different from the usual configuration of this type of printer.

The front/back detection unit 4 includes two sets of feeding mechanisms 5 and 6, and a first
The feeding mechanism 5 includes a first feeding roller 8 driven by a motor 7.
and a first pinch roller 9.

Further, the second feed mechanism 6 includes a second feed roller 11 and a second pinch roller 12 that are driven by another motor 10. Here, the two motors 7 and 10 are driven by a motor control circuit 13.
The rotational speeds of these motors are set so that the peripheral speed R of the second feed roller 11 is slightly higher than the rotational peripheral speed r of the first feed roller 8 (r<R).

In this way, the paper 1a that is sandwiched between the first feeding mechanism 5 and fed to the second feeding mechanism 6 is pulled by the second feeding mechanism from the time it is pinched by the second feeding mechanism having a high peripheral speed, and This results in frictional forces between the feed mechanism and the paper.

In this invention, in order to detect and compare the frictional force generated on both the front and back sides of the paper when the paper is pulled as described above, slit disks 14 are installed on the rotating ring of the first feed roller 8 and the rotating shaft of the first pinch roller 9, respectively. A rotation detector consisting of .15 and light 1ota, 17 and photo sensors 18 and 19 is attached. The outputs of these two systems of rotation detectors are input to pulse counters 2G and 21, respectively, and the pulses generated during a predetermined period of time set by the motor control circuit 13 every time one sheet is fed are counted. This counting result reflects the friction between the top surface of the paper and the first feed roller 8 and the friction between the bottom surface of the paper and the first pinch roller 9 when the second feed mechanism 6 pulls the paper 1a, respectively. In other words, the feed roller 8 is connected to the motor so that it can rotate freely in the normal rotation direction beyond the regulation of the motor 7, and the rotational resistance and surface *W of each roller 8 and 9 during free rotation are determined.
If the coefficients are made equal, the slippage of the roller on each side of the paper 1a can be detected from the number of rotations of the roller.

In this case, the side with a lower rotational speed was in contact with a smooth surface with less friction.

Therefore, by inputting the outputs of the two pulse counters 20 and 21 to the comparison circuit 22 and comparing them, it is possible to know the set state of the paper l from the output signals. The coefficient value m of the pulse counter 20 that depends on the rotation of the roller 8 is the same as that of the other pulse counter 21.
When the coefficient value M is larger than (m>M), the comparator circuit 22
If the display lamp 23 or an alarm is used to warn of the condition by issuing a signal from
3 to stop printer operation. In addition, the output signal of this comparison circuit is provided separately in a front-back reversing mechanism 2.
It is also possible to automatically turn the paper upside down and continue printing.

FIG. 2 is a conceptual diagram showing the configuration of an example of such a front-back reversing mechanism. A paper gate 25 is provided after the front/back detection section 4 shown in FIG. When is in a normal state, it passes through the upper normal route,
When setting in the opposite direction, go through the lower reversal route to print section 3.
The front/back reversing mechanism 24 is constructed by appropriately combining a vertical feed roller and a horizontal feed roller (not shown) so that the paper is turned over after sequentially passing through the modes shown in A, B, C, and D in the figure. ing.

In the above embodiment, an example was described in which front/back detection is determined based on the difference in slip between the feed roller and the pinch roller, but in order to detect the friction state between the front and back sides of the paper, it is also necessary to check the rollers when pulling the paper. It is also possible to use a method of looking at the difference in torque.

〔Effect of the invention〕

As is clear from the above description, the main point of this invention is to add a function to a printer that uses cut paper to determine whether the paper is set in the correct or reverse direction based on the difference in friction between the front and back sides of the paper. This eliminates the possibility of printing on the back side with the wrong set of paper, improving operability and ensuring good printing results at all times. It is beneficial to apply and scratch.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the construction of an embodiment of a cant paper printer to which the present invention is applied, and FIG. 2 is a conceptual diagram for explaining the construction of an example of a front-back reversing mechanism. In the figure, 1 is paper, 2 is a paper stacking section, 3 is a printing section,
4 is a front/back detection unit, 5 is a first feed mechanism, 6 is a second feed mechanism, 7 and 10 are motors, 8 is a first feed roller, and 9 is a first feed mechanism.
Pinch roller, 11 is a second feed roller, 12 is a second pinch roller, 14 and 15 are slit disks, 16'EL
and 17 are light sources, and 18 and 19 are photo sensors.

Claims (1)

[Claims] A front/back detection unit is installed in the paper feed path between the printing cut paper stacking unit and the printing unit to compare the friction between the front and back sides of the paper to determine whether the paper is front or back, and its output signal instructs the paper to be reversed. A cut paper printer that is characterized by: