JPH10293499A - Page printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a page printer capable of printing on printing paper regardless of paper thickness by providing a mechanism capable of varying the temperature and the pressure of a fixing device in accordance with the paper thickness. SOLUTION: As for the temperature control of a heating roller 2 in accordance with the paper thickness; three thermosensors 3 are installed inside the roller 2 so that one of them is set at the center of paper width, that is, the center of the roller 2, and further two are equally set on both sides one by one. Then, three themosensors 3 are constituted to realize the enlargement of the temperature variable area and the uniformity of the surface temperature of the roller 2 by an electronic control circuit. As for the pressure control of the roller 5 in accordance with the paper thickness; the spring loading of a spring for a pressure roller 6 is varied by a tension system so as to realize the step variation of the spring loading of the spring 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer
The present invention relates to a printer, which is a printing device of device A.

[0002]

2. Description of the Related Art A conventional technique will be described below with reference to the drawings.

FIG. 3 is a sectional view showing a general internal structure of a page printer according to the prior art.

In FIG. 3, reference numeral 20 denotes cut-sheet paper as printing paper, reference numeral 21 denotes a paper feed tray, reference numeral 22 denotes a paper feed roller, reference numeral 23 denotes a transport roller, reference numeral 24 denotes a transfer charger, reference numeral 25 denotes a discharge lamp,
6 is a cleaning blade, 27 is a waste toner tank, 2
8 is a fixing device, 29 is a heating roller of the fixing device, 30 is a heating lamp heater inside the heating roller 29, 31 is a pressing roller of the fixing device, 32 is a pressing roller spring, 33 is a separation claw, 34
Is a discharge roller, 35 is a paper path switching claw, 36 is a photosensitive drum, 37 is a charge unit, 38 is a toner cartridge, 39 is a developing device roller, 40 is a toner transfer roller,
41 is a toner stirrer and 42 is an optical unit.

First, a printing process according to the prior art will be described. In FIG. 1, when a printer receiving data from a computer enters a printing start state, the paper feed tray 21
The cut-sheet paper 20 set in is set to be fed one by one by a feed roller 22. The transport rollers 23 align the heads of the cut sheets 20 even if there is some skew during paper feeding, and the cut sheets 20 are conveyed straight. When the cut sheet 20 approaches the transfer charger 24 below the photosensitive drum 36, the toner in the toner cartridge 38 is transferred to the photosensitive drum 36 that has been irradiated by the optical unit 42 in accordance with the print data. Since the toner of the developing device roller 39 attached via the roller 40 is transferred, the toner on the photosensitive drum 36 starts to be transferred to the cut sheet 20 by the transfer charger 24 in synchronization with the paper conveyance. Immediately after the transfer, the charge removal of the photosensitive drum 36 is performed by the charge removal lamp 25. On the other hand, after the toner on the surface of the photosensitive drum 36 is cleaned by the cleaning blade 26, the photosensitive drum 36 is primarily charged by the charging unit 37, and the process shifts again to the process of irradiating the next data by the optical unit 42. In the steps so far, the toner transferred onto the cut sheet 20 is still on the paper. Only after passing through the next fixing device 28, the toner is fixed to the surface of the cut sheet 20. The fixing method of the toner is as follows.
Heating of the heating roller 29 by the internal heating lamp heater 30 and the pressure roller spring 3 of the pressure roller 31 of the fixing device 28
2 is applied to the cut sheet 20 at the same time. At this time, cut sheet 20
Is heated and pressurized, so that winding around the heating roller may occur. As a countermeasure, a separating claw 33 is provided. According to the mode of the paper path switching claw 34, the cut sheet 20 that has passed through the discharge roller 34 has the print surface of the cut sheet 20 turned upside down, that is, face-up discharge, or the print surface of the cut sheet 20 is placed on the back. By selecting one of the following states, that is, face-down discharge, discharge is performed in each state. Such a printing process has been established because a printing paper needs to weigh 55 kg or more in a conventional page printer.

[0006]

However, in the above-described conventional page printer, the peeling caused by heating and pressurizing in a fixing device due to the strength of the paper quality, for printing paper having a small paper thickness. There was a problem of paper jam due to failure. Also, with conventional page printers, compared to single-sheet paper, which requires a certain amount of paper thickness, continuous paper, which is actually used in the market, has a wider range of paper thickness. However, there has been a problem that printing cannot be performed due to the complicated paper transport mechanism.

Accordingly, the present invention provides a page printer capable of printing on printing paper regardless of the paper thickness by providing a mechanism capable of changing the temperature and pressure of the fixing device according to the paper thickness. The purpose is to do. Further, the present invention provides a page printer capable of printing on both cut sheet and continuous form paper by providing the sheet transport mechanism with both a cut sheet and continuous form paper. Aim.

[0008]

According to the first aspect of the present invention,
It is characterized by having a mechanism capable of changing the temperature and pressure of the fixing device in accordance with the thickness of the printing paper.

The invention according to claim 2 is characterized in that the paper transport mechanism has both a single-sheet paper and a continuous-sheet paper transport mechanism.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of a fixing device section mechanism of a page printer according to the present invention, and FIG. 2 is a schematic sectional view of a paper transport mechanism of a page printer according to the present invention. In FIG. 1, 1 is a printing paper, 2 is a heating roller in a fixing device, 3 is a heating lamp heater in the heating roller 2, 4 is a thermosensor in the heating roller 2, and 5 is a heating sensor in the fixing device. The pressure roller, 6 denotes a pressure roller spring, and 7 denotes a separation claw.
In FIG. 2, 8 is a continuous form paper, 9 is a paper feed tractor, 10 is a face-up discharge tractor, 11 is a face-down discharge tractor, 12 is a paper feed tray, 13 is a cut sheet, 14 is a paper feed roller, 15 is a conveying roller, 16 is a photosensitive drum, 1
7 is a transfer charger, 18 is a heating roller of a fixing unit, 1
Reference numeral 9 denotes a pressure roller of the fixing unit.

Referring to FIG. 1, a description will be given of a heating control mechanism of the heating roller 2 and a pressure control mechanism of the pressure roller 5 in the embodiment of the present invention. Referring to FIG. 2, a paper transport mechanism according to an embodiment of the present invention will be described.

In FIG. 1, the temperature control according to the paper thickness of the heating roller 2 realizes the present invention by making it possible to expand the temperature variable range and make the roller surface temperature uniform. Further, the pressure control according to the paper thickness of the pressure roller 5 realizes the present invention by making the spring load of the pressure roller spring 6 variable.

First, in the temperature control according to the paper thickness of the heating roller 2, the number of thermosensors 3 inside the heating roller 2 is set to one at the center of the paper width, that is, one at the center of the heating roller 2, and one at each of both sides. , A total of three are installed. The three thermosensors 3 are realized by an electronic control circuit to expand the temperature variable range of the heating roller 2 and to make the surface temperature uniform.

The pressure control according to the paper thickness of the pressure roller 5 is as follows.
By varying the spring load of the pressure roller spring 6 by a tension method, the spring load of the pressure roller spring 6 can be varied in steps. Any of the temperature and pressure controls employs an automatic selection method or a manual switch switching method to synchronize with the paper thickness of the printing paper, thereby enabling a more convenient page printer.

In FIG. 2, the printing paper switching mode for the continuous paper 8 and the cut paper 13 is provided in the control circuit and is performed by a selection switch. This is because the sheet width of the continuous form paper 8 and the cut sheet 13 are different, and it is determined whether the paper feed tractor 9, the face-up discharge tractor 10, and the face-down discharge tractor 11 are simply driven without raising or lowering the paper. This is realized by detecting with a sensor. A tractor for transporting the continuous form paper should be installed in the paper feeding section and the discharge section, and synchronized control should be performed so that the tractor pin is entangled in the feed hole of the continuous form paper. This process is realized by a mechanism exactly the same as that for single-sheet paper.

[0017]

According to the first aspect of the present invention, since the pressure and temperature of the fixing device can be changed according to the thickness of the printing paper, the printing paper can be changed regardless of the paper thickness. Can be printed.

According to the second aspect of the present invention, since the paper transport mechanism has both a single-sheet paper and a continuous-sheet paper, printing can be performed on both the single-sheet paper and the continuous-sheet paper. can do.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a fixing unit mechanism of a page printer according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a paper transport mechanism of the embodiment of the page printer to which the present invention is applied.

FIG. 3 is a cross-sectional view of a general internal structure of a page printer according to the related art.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 printing paper 2 heating roller in fixing device 3 heating lamp heater inside heating roller 2 4 thermosensor inside heating roller 2 5 pressure roller in fixing device 6 spring for pressure roller 7 separation claw 8 continuous paper Reference Signs List 9 paper feed tractor 10 face-up discharge tractor 11 face-down discharge tractor 12 paper feed tray 13 cut sheet 14 paper feed roller 15 transport roller 16 photosensitive drum 17 transfer charger 18 heating roller of fixing unit 19 pressure roller of fixing unit REFERENCE SIGNS LIST 20 cut sheet 21 paper feed tray 22 paper feed roller 23 transfer roller 24 transfer charger 25 static elimination lamp 26 cleaning blade 27 waste toner tank 28 fixing device 29 fixing device heating roller 30 heating lamp heater 31 fixing device pressure roller 32 Spring for pressure roller 33 Separation claw 34 Discharge roller 35 Paper thread Switching claw 36 photosensitive drum 37 charged units 38 toner cartridge 39 developer roller 40 toner transfer roller 41 the toner agitator 42 optical unit

Claims (2)

[Claims] An image forming apparatus comprising: a mechanism capable of changing a pressure and a temperature of a fixing device according to a paper thickness of a printing paper; and capable of printing on the printing paper regardless of the paper thickness. Page printer. 2. The paper conveying mechanism according to claim 1,
A page printer having a paper transport mechanism for both cut sheets and continuous forms, and capable of printing on both forms.