KR20000002631A - Printer - Google Patents

Abstract

PURPOSE: A printer is provided to intercept electric power supply to a printing engine by deciding if the printing engine is out of order. CONSTITUTION: The printer comprises:a clock generator(71) generating the clock signal of a frequency; a first counter and a second counter generating an abnormal signal if a count value is reached the value of the stated time by inputting and counting the clock signal; and OR gate(75) outputting an output signal from the second counter to a switch control part.

Description

printer

The present invention relates to a printing press, and more particularly, to a printing press that can cut off power supply to a printing engine when an abnormality occurs in a control system for controlling a printing engine.

A typical wet color printer is shown in FIG. 1.

Referring to the drawings, a wet printing machine using a developer in which a toner and a liquid carrier element are mixed as a developer is provided with a photosensitive belt which is circulated by three rollers 11, 12, 13 arranged in a triangle shape. Adjacent to the circulation path of 14, it has a printing engine including a reset device 15, a light scanning device 16, a developing device 17, a drying device 18, a transfer device 20.

The drying device 18 is a drying roller 18a for adsorbing the liquid carrier element remaining on the photosensitive belt 14 and a liquid carrier adsorbed to the drying roller 18a while being rotated in engagement with the drying roller 18a. Two heating rollers 19 are provided for evaporating the urea. In each heating roller 19, the heater 19a is provided.

The transfer device 20 is a transfer roller 21 for transferring an image formed of toner on the photosensitive belt 14 while rotating in contact with the photosensitive belt 14, and the image transferred to the transfer roller 21 is a sheet of paper 23. A fixing roller 22 which is engaged with the transfer roller 21 and rotates is provided to be fixed thereto. Heaters 21a and 22a are also incorporated in the transfer roller 21 and the fixing roller 22.

Looking at the printing process, first, the optical scanning device 16 scans the light corresponding to the image information to be printed on the predetermined area of the photosensitive belt 14 through the reset device 15 for initializing the new electrostatic latent image do. Through this process, the electrostatic latent image is formed on the photosensitive belt 14. Thereafter, the developing unit 17 supplies a developing solution in a liquid state to the photosensitive belt 14 in the area where the electrostatic latent image is formed to develop an image. The drying device 18 adsorbs and evaporates the liquid carrier element remaining on the photosensitive belt 14. Then, the image formed on the photosensitive belt 14 is transferred from the photosensitive belt 14 to the transfer roller 21 by the continuous movement of the photosensitive belt 14. The image transferred to the transfer roller 21 is transferred to the paper 23 entering between the transfer roller 21 and the fixing roller 22 by a paper feeder (not shown) so that a desired image is printed on the paper 23. do.

In the printing machine capable of performing the above printing process, in the case of the transfer roller 21, the fixing roller 22, the heating roller 19 of the conditions that each device must be equipped for the normal printing operation The heat must be maintained at the specified temperature for each of its surfaces. For this purpose, a temperature measuring instrument (not shown) for measuring the surface temperature of each roller 19, 21, 22 is provided, and mounted in each roller 19, 21, 22 using information provided from the temperature measuring instrument. An on / off drive for power supply of the heated heaters 19a, 21a, 22a is controlled by an engine controller (not shown) that controls the operation of the printing engines. However, when an abnormality occurs in the central processing unit constituting the engine control unit, normal control of the print engine is not performed, and in particular, when normal temperature control of each heater 19a, 21a, 22a is not performed. That is, even if the surface temperature of each roller 19, 21, 22 exceeds the prescribed temperature, if the power supply cutoff to the heaters 19a, 21a, 22a is not controlled, the photosensitive belt 14 that is weak to heat There is a problem that is easily damaged by the transfer roller 21 and the drying roller (18a) that generates heat exceeding the prescribed temperature.

The present invention was devised to improve the above problems, and when an abnormality occurs in the engine control unit for controlling the print engine, a printer capable of controlling the power supply to the print engine so as to suppress damage to the print engine. The purpose is to provide.

1 is a cross-sectional view showing a general wet printing machine,

2 is a block diagram showing a printing press according to the present invention,

FIG. 3 is a block diagram illustrating an example of a configuration of an abnormality determining unit of the printer of FIG. 2.

<Description of the reference numerals for the main parts of the drawings>

11, 12, 13: roller 14: photosensitive belt

15: reset device 16: optical scanning device

17: developing device 18: transfer device

18a: transfer roller 19: heating roller

19a, 21a, 22a: Heater 20: Transfer device

21: transfer roller 22: fixing roller

23: paper 30: printing control unit

31: central processing unit (CPU) 32: photosensitive belt meandering calculation unit

33: input and output control unit 34: scanning synchronization data storage unit

35: bus 35a: signal line

41: main control unit 42: input device

43: display device 50: power supply

60: print engine 70: abnormality determination unit

71: clock generator 72: first counter

73: second counter 74: inverter

75: OR gate 80: switch section

80a: switch member 80b: coil portion

81: power supply line

In order to achieve the above object, according to the present invention, there is provided a light scanning device, a developing engine, a print engine including a heater, a central processing unit for controlling the overall operation of the printing engine, and the center to assist the control of the printing engine. In a printing machine having an engine control unit including peripherals connected by a processing device and a bus of a plurality of signal lines, at least one signal line whose input is selected on the bus to determine whether the central processing unit is abnormally operated. And an abnormality determining unit configured to generate an abnormal signal when the level of the signal input through the input terminal does not change for a predetermined time, and when the abnormal signal is input, power is supplied from the power supply to the printer engine. It is provided with a switch unit installed to open the power supply line.

Preferably, the abnormality determination unit is a clock generator for generating a clock signal of a predetermined frequency, and the clock signal is input to each of the common input and count while counting while the count value reaches a value corresponding to the set time to generate an abnormal signal An OR gate which receives a signal output from each of a first counter and a second counter, the first counter and the second counter, and outputs the logic operation to the switch control unit, and the reset terminal of the first counter includes the selected signal line And a reset terminal of the second counter is connected to an output terminal of an inverter for inverting and outputting a signal transmitted through a signal line connected to the first counter.

Hereinafter, with reference to the accompanying drawings will be described in more detail the printing press according to the present invention.

2 is a block diagram showing a printing machine according to the present invention. Elements having the same function as in Fig. 1 are denoted by the same reference numerals.

Referring to the drawings, the printer is the main control unit 41, the input device 42, the display device 43, the engine control unit 30, the power supply 50, the print engine 60, the abnormality determination unit 70 And a switch unit 80.

The main controller 41 controls the overall printing press, and converts the image information received from a computer (not shown) connected by an external device, for example, by a communication interface or into engine print data and handed it to the engine controller 30. . The input device 42 is provided to instruct setting and change of various printing functions provided, and the display device 43 receives the print job contents, error messages, and the like from the main control unit 41 and displays them.

In the case of the wet electrophotographic printing system, the print engine 60 may include a photosensitive medium such as a photosensitive belt, a light scanning device 16 that scans the photosensitive medium with light, and forms an electrostatic latent image, and an electrostatic latent image. A developer 17 for developing with a developer, a drying device 18 for adsorption and evaporation of a liquid carrier element, a transfer device 20 for transferring an image formed by a developer onto a photosensitive medium to paper, and a sheet of paper supplied to the transfer device 20 A paper feeder 25 is provided. In the drying apparatus 18 and the transfer apparatus 20, heaters 19a, 21a, 22a are incorporated.

The engine control unit 30 controls each device of the print engine 60 so that an image corresponding to the received print data can be printed on paper. Looking at the engine control unit 30, a central processing unit (CPU) 31 and a photosensitive belt meandering amount calculating unit 32, an input / output control unit 33, and a scanning synchronous data storage unit 34 are provided as peripheral devices. The central processing unit 31 and the peripheral device are interconnected by a bus 35 including address signal lines, data signal lines, read / write command signal lines, and the like. Of the peripheral devices assisting the control operation of the central processing unit 31 in order to properly control the printing operation conditions, the photosensitive belt meandering amount calculating unit 32 is used to obtain information on the degree of deviation of the photosensitive belt. Light installed so as to generate a light receiving signal corresponding to the degree to which a part of the light receiving area is covered by the photosensitive belt with respect to the light scanned from the optical scanning device 16 to cross the belt or the light irradiated from a separate light source. By receiving the output signal of the detector to calculate the meandering amount for the degree of deviation of the photosensitive belt, and provides the calculated value to be used for engine control of the central processing unit (31). The input / output control unit 33 relays information exchange between the central processing unit 31 and the printing engine 60. The scanning synchronization data storage unit 34 outputs the image information from the engine control unit 30 to the optical scanning device 16 so that the pixel unit image information can reach the pixel position set on the photosensitive belt without departing. Synchronization data for output timing is stored.

The central processing unit 31 of the engine control unit 30 having such a structure exchanges information with peripheral devices at any time during the print job preparation period, the waiting period, and the print job after the power is turned on.

In the present invention, focusing on the fact that the control operation for controlling the printing engine 60 of the central processing unit 31 is continuously performed by the transmission and reception of a signal through the bus 35, some signal lines of the bus 35 The abnormality determination unit 70 is provided to monitor whether the signal transmission is continuously performed and to determine whether the central processing unit 31 is operating abnormally. To this end, the abnormality determination unit 70 switches the abnormal signal if its input terminal is connected with at least one signal line selected from the bus 35 and the potential level of the signal input through the input terminal does not change for a set time. Occurs in the unit 80. Among the data signal line, the address signal line, and the read / write instruction signal line for monitoring the abnormality determining unit 70, a signal line with a high frequency of signal transmission / reception between the CPU and the peripheral device is selected. desirable. The comparison setting time for the presence or absence of a signal change for abnormality determination of the abnormality determination unit 70 is determined in consideration of the driving characteristics of the print control unit 30 with respect to the selected signal line.

The switch unit 80 is installed to open the power supply line 81 for supplying power from the power supply 50 to the print engine 60 when an abnormal signal is input from the abnormality determination unit 70. The switch unit 80 is provided on the power supply line between the external power source and the printer or from the power supply 50 installed in the printer so as to open / close the power supply line for supplying power to the entire printing engine 60. The apparatus may be installed on a power supply line connecting the printing engine 60, and may cause damage to itself and other equipment if the power supply is not cut off. For example, heaters 21a and 22a installed in the transfer apparatus 20. And the power supply line 81 to the heaters 19a installed in the drying device 18 may be cut off.

A specific configuration example of the abnormality determination unit is shown in FIG. 3.

Referring to the drawings, the abnormality determination unit 70 includes a clock generator 71, two counters 72 and 73, an inverter 74, and an OR gate 75. The case where power is supplied to a heater group including heaters 19a, 21a, 22a of the transfer device and the drying device through a 24V power supply line of the power supply 50 is shown.

The clock generator 71 for generating a clock signal of a predetermined frequency may be provided separately. Preferably, a clock generator provided in the engine controller 30 is used to supply a clock signal to the central processing unit 31.

The first and second counters 72 and 73 receive and count clock signals provided from the clock generator 71, and there is no change in the signal input through the selected signal line 35a, so that the count value is set. When the value corresponding to time is reached, an abnormal signal is generated. At this time, irrespective of the signal level holding state of the signal line 35a, i.e., if the signal line 35a remains unchanged until it reaches a time set to either the high level or the low potential level, an abnormal signal is generated. The reset terminal 72a of the first counter 72 is connected to the selected signal line 35a, and the reset terminal 73a of the second counter 73 is connected to the first counter 72. It is connected to the output terminal of the inverter 74 which inverts and outputs the signal transmitted through 35a). Signals output from the first counter 72 and the second counter 73, respectively, are ORed together by the OR gate 75 and are output to the switch unit 80.

The switch unit 80 includes a switch member 80a installed to open / close the power supply line 81 between the output terminal of the power supply 50 and the heaters according to the output signal of the OR gate 75, and It has the coil part 80b which interrupts the switch member 80a and controls ON / OFF of the switch member 80a. When the output of the OR gate 75 is high level, the coil portion 80b generates magnetic force by electric current conduction. The switch member 80a formed of a material sensitive to magnetic force is installed so that the switch is turned on or off by the generated magnetic force.

Therefore, when the information exchange between the central processing unit 31 and the peripheral device is normally performed, the binary signal, that is, the low level signal and the high level signal are randomly repeated through the signal line 35a monitored by the abnormality determination unit 70. And the first and second counts 72 and 73 which count the clock signals accordingly are repeated before the set time is reached. As a result, when the first and second counters 72 and 73 reach the set time value, the high-level signal is output, and the switch member 80a is switched off when the magnetic force is generated. In the normal operation of 31, the switch member 80a is kept on by the low level output signal from the first and second counters 72 and 73. On the contrary, when the central processing unit 31 is damaged and the operation is stopped, signal transmission and reception with the peripheral device through the signal line 35a is not performed. In the abnormal operation of the central processing unit 31, the signal level of the signal line 35a is fixed. As a result, if the signal level input to the counters 72 and 73 through the connected signal line 35a is not inverted for a set time, either one of the first counter 72 or the second counter 73 becomes a high level. The abnormal signal is output. The generation of the high level abnormal signal leads to the current conduction of the coil portion 80b and the switch-off of the switch member 80a, and as a result, the power supply to the heaters 19a, 21a, 22a is cut off. In the illustrated example, the abnormality determination unit 70 is supplied with driving power from the power supply line 5V 82 which is separated from the power supply line 81 supplied to the heaters 19a, 21a, and 22a. Thus, the switch-off of the switch unit 80 can be maintained continuously.

On the other hand, unlike the illustrated example, when the switch unit 80 is installed so as to cut off the power supply from the external AC power supply 90 to the power supply 50, the power supply cutoff to the power supply 50 is continuously A separate battery is provided for supplying driving power to the abnormality determining unit 70 so as to be maintained.

As described so far, the printing press according to the present invention is further provided with safety means for judging whether there is an abnormality in the printing engine control system and to cut off the power supply to the printing engine, thereby damaging the apparatus when the printing engine control system has an abnormality. Can be prevented.

Claims (5)

A photonic scanning device, a print engine including a developing device and a heater, a central processing unit controlling overall operation of the printing engine, and a bus including a plurality of signal lines to the central processing unit to assist control of the printing engine. In a printing machine having an engine control unit including the peripherals, The input terminal is connected to at least one signal line selected on the bus to determine whether the central processing unit is abnormally operated, and generates an abnormal signal when the level of a signal input through the input terminal does not change for a predetermined time. Abnormality determination unit; And a switch unit installed to open a power supply line for supplying electric power from a power supply to the printer engine when the abnormal signal is input. The method of claim 1, wherein the abnormality determination unit A clock generator for generating a clock signal of a predetermined frequency; A first counter and a second counter which generate an abnormal signal when the count signal reaches a value corresponding to a set time while counting the clock signals in common; And an OR gate which receives the signals output from the first counter and the second counter, respectively, and performs a logic operation to output the signals to the switch controller. The reset terminal of the first counter is connected to the selected signal line, and the reset terminal of the second counter is connected to an output terminal of the inverter for inverting and outputting a signal transmitted through the signal line connected to the first counter. A printing press, characterized in that. The printer as claimed in claim 2, wherein the clock signal is also supplied to the central processing unit. The method of claim 1, wherein the switch unit And a power supply line configured to open a power supply line for supplying power from the power supply to the heater. The method of claim 4, wherein the switch unit A switch member provided on the power supply line so as to be switched on or off by magnetic force; And a coil unit generating magnetic force in the switch according to the abnormal signal.