JP2013086477A - Printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the influence of various kinds of a heat generating source in an inside of a printing device exerted on a printing part.SOLUTION: In an inside of a first casing, an air curtain is formed between the heat generating source such as a sheet drying part or a humidified gas generation part, and the printing part. A control part as another heat generating source is stored in a second casing different from the first casing. The gas forming the air curtain is introduced into the second casing in order to cool the control part.

Description

  The present invention relates to an inkjet printing apparatus.

  In an ink jet printing apparatus, a print unit including a print head is particularly susceptible to heat generated by a heat source in the apparatus. When the print head receives heat, the ink from the ink discharge nozzles may dry and become undischargeable. In addition, the conveyance mechanism that conveys the sheet in the printing unit may change the clearance of the components due to heat and change the conveyance state of the sheet from the original state, which may reduce the print quality.

  In order to solve this problem, in the printing apparatus disclosed in Patent Document 1, the printing unit and the fixing unit are each surrounded by a case, outside air is taken into the printing unit from the duct, and heat is discharged to the outside of the fixing unit. A duct is provided.

JP 2006-175645 A

  In the configuration of Patent Document 1, heat generated in the fixing unit is blocked by the wall of the case. However, when the heat generation amount of the heat generation source is large, this alone may not sufficiently block the heat and affect the print unit. Although there is no specific description in Patent Document 1, various other heat sources can exist inside the printing apparatus. For example, a control board and power supply for control are large heat sources. It is necessary to suppress the heat generated by various heat sources of these printing apparatuses from affecting the printing unit.

  The present invention has been made based on recognition of the above-described problems. An object of the present invention is to provide a printing apparatus in which the influence of various heat sources of the printing apparatus is prevented from affecting the printing unit.

  The printing apparatus of the present invention includes a printing unit that prints on a conveyed sheet that includes an inkjet printhead, a drying unit that includes a heater and dries the printed sheet, and a generation unit that includes a heater and generates humidified gas. A supply unit that supplies the humidified gas to the print unit; a first housing that houses the print unit, the drying unit, the generation unit, and the supply unit; a control unit that controls the apparatus; A second housing different from the first housing in which the control unit is housed, and in the first housing, between at least one of the drying unit and the generating unit and the printing unit Means for forming an air curtain in the space of the air, and the gas forming the air curtain discharged from the first housing is introduced into the second housing for cooling the control unit. Characterize

  An object of the present invention is to realize a printing apparatus that suppresses the influence of various heat sources of the printing apparatus on the printing unit.

Schematic showing the internal configuration of the printing device Perspective view for explaining the operation of the air curtain system Cross-sectional view for explaining the operation of the air curtain system Upper cross-sectional view for explaining the operation of the air curtain system Block diagram of control unit A graph showing the temperature change of the print unit as the machine moves

  Hereinafter, an embodiment of a printing apparatus using an inkjet method will be described. The printing apparatus of this example is a high-speed line printing apparatus that uses a continuous sheet wound in a roll shape and supports both single-sided printing and double-sided printing. For example, it is suitable for the field of printing a large number of sheets in a print laboratory or the like. The present invention can be applied to a printing apparatus such as a printing apparatus, a printing apparatus multifunction peripheral, a copying machine, and a facsimile apparatus. In addition, the present invention is not limited to a printing apparatus, and industrial equipment (manufacturing apparatus for various devices, inspection apparatus, etc.) used in a factory or the like in which a user designates an apparatus operating time and requires a long time for initialization at startup. The present invention can be widely applied to various devices such as.

  FIG. 1 is a schematic cross-sectional view showing the internal configuration of the printing apparatus. The printing apparatus according to the present embodiment can perform double-sided printing on the first surface of the sheet and the second surface on the back surface side of the first surface using the sheet wound in a roll shape. The printing apparatus includes a sheet supply unit 1, a decurling unit 2, a skew correction unit 3, a printing unit 4, an inspection unit 5, a cutter unit 6, an information recording unit 7, a drying unit 8, a reversing unit 9, a discharge conveyance unit 10, and a sorter. Unit 11, discharge unit 12, humidification generation unit 20, cooling unit 30, and control unit 200. A sheet is conveyed by a conveyance mechanism including a roller pair and a belt along a sheet conveyance path indicated by a solid line in the drawing, and is processed in each unit.

  The sheet supply unit 1 is a unit for holding and supplying a continuous sheet wound in a roll shape. The sheet supply unit 1 can store two rolls R <b> 1 and R <b> 2, and is configured to selectively pull out and supply a sheet. The number of rolls that can be stored is not limited to two, and one or three or more rolls may be stored.

  The decurling unit 2 is a unit that reduces curling (warping) of the sheet supplied from the sheet supply unit 1. The decurling unit 2 uses two pinch rollers for one driving roller, and curls the sheet by curving and passing the sheet so as to give the curl in the opposite direction, thereby reducing the curl. The drive roller of the decurling unit 2 has a built-in heater, and the curl reduction effect is enhanced by applying a decurling force while the sheet is heated.

  The skew correction unit 3 is a unit that corrects skew (inclination with respect to the original traveling direction) of the sheet that has passed through the decurling unit 2. The sheet skew is corrected by pressing the sheet end on the reference side against the guide member.

  The printing unit 4 is a unit that forms an image by performing a printing process on the conveyed sheet from above with the print head 14. The printing unit 4 includes a plurality of conveyance rollers that convey the sheet. The print head 14 has a line type print head in which an inkjet nozzle row is formed in a range that covers the maximum width of a sheet that is supposed to be used. The print head 14 has a plurality of print heads arranged in parallel along the transport direction. In this example, there are seven print heads corresponding to seven colors of C (cyan), M (magenta), Y (yellow), LC (light cyan), LM (light magenta), G (gray), and K (black). . The number of colors and the number of print heads are not limited to seven. As the inkjet method, a method using a heating element, a method using a piezo element, a method using an electrostatic element, a method using a MEMS element, or the like can be adopted. Each color ink is supplied from the ink tank to the print head 14 via an ink tube.

  In the printing unit 4, a humidified humidified gas is supplied to a space where the nozzles of the print head 14 are exposed, and the drying of the nozzles is suppressed. Details will be described later.

  The inspection unit 5 optically reads the inspection pattern or image printed on the sheet by the printing unit 4 using a scanner, and inspects the nozzle state of the print head, the sheet conveyance state, the image position, etc., and the image is printed correctly. This is a unit for determining whether or not. The scanner has a CCD image sensor and a CMOS image sensor.

  The cutter unit 6 is a unit including a mechanical cutter that cuts a printed sheet into a predetermined length. The cutter unit 6 also includes a plurality of conveyance rollers for sending out the sheet to the next process.

  The information recording unit 7 is a unit that records print information (unique information) such as a print serial number and date in a non-print area of the cut sheet. Recording is performed by printing characters and codes using an inkjet method, a thermal transfer method, or the like.

  The drying unit 8 is a unit for heating the sheet printed by the printing unit 4 and drying the applied ink in a short time. Inside the drying unit 8, hot air is applied at least from the lower surface side to the passing sheet to dry the ink application surface. The drying method is not limited to the method of applying hot air, and may be a method of irradiating the sheet surface with electromagnetic waves (such as ultraviolet rays and infrared rays).

  The reversing unit 9 is a sheet winding unit for temporarily winding a continuous sheet that has been printed on the front (front) surface when performing double-sided printing and inverting the front and back. The reversing unit 9 is provided in the middle of a route (loop path) from the drying unit 8 through the decurling unit 2 to the printing unit 4 for supplying the sheet that has passed through the drying unit 8 to the printing unit 4 again. The reversing unit 9 includes a winding rotary body (drum) that rotates to wind the sheet. The continuous sheet that has been printed on the surface and has not been cut is temporarily wound around the winding rotary member. When the winding is completed, the winding rotary member rotates in the reverse direction, and the wound sheet is supplied to the decurling unit 2 and sent to the printing unit 4. Since this sheet is turned upside down, the printing unit 4 can print on the back side.

  The discharge conveyance unit 10 is a unit for conveying the sheet cut by the cutter unit 6 and dried by the drying unit 8 and delivering the sheet to the sorter unit 11. The sorter unit 11 is a unit for sorting printed sheets for each group as necessary. The sorted sheets are discharged to the discharge unit 12 including a plurality of trays.

  The humidification generating unit 20 is a unit for generating a humidified gas (air) and supplying the humidified gas (air) to the sheet before printing, and supplying the humidified gas to the space between the print head 14 and the sheet of the printing unit 4 to generate an air flow. . Humidification by the humidification generation unit 20 suppresses ink drying of the nozzles of the print head 14.

  As the humidification method of the humidification generation unit 20, a vaporization method, a water spray method, a steam method, or the like is adopted. As the vaporization type, there are a moisture permeable membrane type, a dropping permeation type, a capillary type and the like in addition to the rotation type of the present embodiment. The water spray type includes an ultrasonic type, a centrifugal type, a high-pressure spray type, and a two-fluid spray type. The steam type includes a steam piping type, an electric heating type, and an electrode type.

  The humidification production | generation part 20 produces | generates humidification gas to a sheet | seat. In front of the print head 14, a first supply port 21 for supplying a humidified gas to the sheet before printing in order to increase the moisture content of the sheet, and a humidified gas is supplied to the space between the print head 14 and the sheet. A second supply port 22 is provided for this purpose. The humidification production | generation part 20 and the 1st supply port 21 and the 2nd supply port 22 which are supply parts of humidification gas are connected by the duct 24. FIG. Furthermore, the humidification production | generation part 20 and the drying part 8 are connected by the duct 23. FIG.

  The drying unit 8 generates a humid and high-temperature gas when the sheet is dried. Part of this gas (heat) is introduced into the humidification generating unit 20 through the duct 23 and used as auxiliary energy for generating the humidified gas in the humidification generating unit 20. Part of the humidified gas generated by the humidification generating unit 20 is supplied toward the sheet surface through the first supply port 21 before the print head 14. Further, a part of the humidified gas generated by the humidification generating unit 20 is introduced from the upstream side into the space immediately below the print head 14 through the second supply port 22, and the flow of the humidified gas from the upstream toward the downstream is formed. The

  The control unit 200 is a unit that controls each unit of the entire printing apparatus. The control unit 200 includes a controller (control unit) including a CPU, a storage device, and various control units. Further, an external interface 205 and an operation unit 206 for user input / output are provided. The operation of the printing apparatus is controlled based on a command from a host device 211 such as a controller or a host computer connected to the controller via an external interface.

  FIG. 5 is a block diagram illustrating the concept of the control unit 200. The control unit 200 (range surrounded by a broken line) includes a CPU 201, a ROM 202, a RAM 203, an HDD 204, an image processing unit 207, an engine control unit 208, and an individual control unit 209. A CPU 201 (central processing unit) controls the operation of each unit of the printing apparatus in an integrated manner. The ROM 202 stores programs executed by the CPU 201 and fixed data necessary for various operations of the printing apparatus. The RAM 203 is used as a work area for the CPU 201, used as a temporary storage area for various received data, and stores various setting data. The HDD 204 (hard disk) can store and read programs executed by the CPU 201, print data, and setting information necessary for various operations of the printing apparatus.

  A dedicated processing unit is provided for units that require high-speed data processing. An image processing unit 207 performs image processing of print data handled by the printing apparatus. The color space (for example, YCbCr) of the input image data is converted into a standard RGB color space (for example, sRGB). Various image processing such as resolution conversion, image analysis, and image correction is performed on the image data as necessary. Print data obtained by these image processes is stored in the RAM 203 or the HDD 204. The engine control unit 208 performs drive control of the print head 14 of the print unit 4 according to print data based on a control command received from the CPU 201 or the like. The engine control unit 208 also controls the transport mechanism of each unit in the printing apparatus. The individual control unit 209 includes a sheet supply unit 1, a decurling unit 2, a skew correction unit 3, an inspection unit 5, a cutter unit 6, an information recording unit 7, a drying unit 8, a reversing unit 9, a discharge conveyance unit 10, and a sorter unit 11. , A sub-controller group for individually controlling the units of the discharge unit 12 and the humidification generation unit 20. The individual control unit 209 further controls the output of a fan of an air curtain system described later. Based on a command from the CPU 201, the operation of each unit is controlled by the individual control unit 209. The external interface 205 is an interface (I / F) for connecting the controller to the host device 211, and is a local I / F or a network I / F. The above components are connected by the system bus 210.

  The basic operation during printing will be described. Since the printing operation differs between single-sided printing and double-sided printing, each will be described.

  In single-sided printing, a sheet supplied from the sheet supply unit 1 and processed by the decurling unit 2 and the skew correction unit 3 is printed on the front side by the printing unit 4. The printed sheet passes through the inspection unit 5 and is cut into predetermined unit lengths set in advance in the cutter unit 6. In the cut sheet, print information is recorded on the back surface of the sheet by the information recording unit 7 as necessary. Then, the cut sheets are conveyed one by one to the drying unit 8 and dried. Thereafter, the sheet is sequentially discharged and stacked on the discharge unit 12 via the discharge conveyance unit 10 and the sorter unit 11.

  In double-sided printing, the back side printing sequence is executed after the front side printing sequence. In the first front surface print sequence, the operation in each unit from the sheet supply unit 1 to the inspection unit 5 is the same as the one-sided printing operation described above. In the cutter unit 6, the cutting operation is not performed, and the continuous sheet is conveyed to the drying unit 8 as it is. After the ink is dried on the surface in the drying unit 8, the sheet is introduced into the path on the reversing unit 9 side, not on the path on the discharge conveyance unit 10 side. The introduced sheet is wound around the winding drum of the reversing unit 9 that rotates in the forward direction (counterclockwise direction in the drawing). When all of the scheduled printing on the front surface is completed in the printing unit 4, the rear end of the printing area of the continuous sheet is cut in the cutter unit 6. The continuous sheet on the downstream side in the conveying direction (printed side) is wound up to the rear end (cut position) of the sheet by the reversing unit 9 through the drying unit 8 with reference to the cutting position. On the other hand, the continuous sheet on the upstream side in the conveyance direction from the cut position is rewound to the sheet supply unit 1 so that the leading end of the sheet (cut position) does not remain in the decurling unit 2.

  After the above front surface print sequence, the back surface print sequence is switched. The winding drum of the reversing unit 9 rotates in the opposite direction (clockwise direction in the drawing) to that during winding. The end portion of the wound sheet (the trailing end of the sheet at the time of winding becomes the leading end of the sheet at the time of feeding) is fed into the decurling unit 2. The decurling unit 2 performs curl correction in the opposite direction. This is because the sheet wound on the winding drum is wound upside down with respect to the roll in the sheet supply unit 1 and is curled in the opposite direction. Thereafter, printing is performed on the back surface of the continuous sheet by the printing unit 4 through the skew correction unit 3. The printed sheet passes through the inspection unit 5 and is cut into predetermined unit lengths set in advance in the cutter unit 6. Since the cut sheet is printed on both sides, recording by the information recording unit 7 is not performed. Cut sheets are conveyed one by one to the drying unit 8, and sequentially discharged and stacked on the discharge unit 12 via the discharge conveyance unit 10 and the sorter unit 11.

  Each unit constituting the printing apparatus is housed separately in a plurality of housings B1, B2, and B3. The second housing B2 accommodates a control board 300 and a power supply 310 that constitute at least a part (a part or all) of the control unit. A sorter unit 11 and a discharge unit 12 are accommodated in the third housing B3. Other units are accommodated in the first housing B1. The large heat sources inside the first housing B1 are the heater of the drying unit 8 and the heater of the humidification generating unit 20. A large heat source inside the second housing B2 is the control board 300 and the power source 310. The reason why the sorter unit 11 and the discharge unit 12 are separated as the third housing B3 is that jamming is likely to occur when the sheets are sorted and discharged, and maintenance for jam recovery is facilitated.

  Inside the first housing B <b> 1, a drying unit 8 and a humidification generation unit 20, which are large heat generation units, are arranged below the printing unit 4. Therefore, the print unit 4 is easily affected by the heat rising from the heat source by convection. When the print head receives heat, the ink from the ink discharge nozzles may dry and become undischargeable. In addition, the conveyance mechanism that conveys the sheet in the print unit 4 may change the clearance of the components due to heat and change the conveyance state of the sheet from the original state, thereby degrading the print quality.

  In order to prevent such a problem in advance, the printing apparatus of the present embodiment is provided with an air curtain system for forming a laminar flow of air (air curtain) between the heat generation source and the print unit to perform heat insulation. It has been.

  2 (perspective view), FIG. 3 (transverse cross-sectional view), and FIG. 4 (upper cross-sectional view) are diagrams for explaining the operation of the air curtain system. The outside air introduced from the introduction portion 100 on the front surface of the first housing B1 flows so as to be discharged from the discharge portion 110 on the back surface of the first housing B1, and an air curtain as shown by an arrow AC in the figure is formed. Is done. The introduction unit 100 is provided with a filter 100A for trapping dust and dust and a fan 100B for generating an air flow for sucking outside air in accordance with an opening provided on the wall surface of the housing. The discharge unit 110 is provided with a filter 110A for trapping dust and dust and a fan 110B for generating an exhaust airflow in accordance with an opening provided on the wall surface of the housing.

  As shown in FIG. 3, the air curtain (arrow AC) is formed in the space between the printing unit 4 and the drying unit 8 and the humidification generation unit 20 that are heat generation units in the Z direction. The high-temperature air rising from the drying unit 8 and the humidification generating unit 20 is blocked by the air curtain and discharged to the outside of the casing together with the airflow of the air curtain, so that heat is not easily transmitted to the printing unit 4. As a result, the printing unit 4 can continue stable and high-quality printing.

  As shown in FIG. 4, the humidified gas flows in the print unit 4 along the direction (X direction) in which the sheet is conveyed with an air flow (arrow AF) immediately below the print head. On the other hand, the air curtain (arrow AC) flows at a position separated in the Z direction so as not to inhibit the flow of the humidified gas in a direction (Y direction) intersecting (orthogonal) with the flow of the humidified gas.

  A temperature sensor 120 is provided as a detector for detecting temperature at the lower part of the print unit 4, and the flow of the air curtain is adjusted according to the detection of the temperature sensor 120. Specifically, the individual control unit 209 controls the air flow rate of the fan 110A and the fan 110B based on the temperature detected by the temperature sensor 120. If the detected temperature exceeds the threshold value, the outputs (rotations per hour) of the fans 110A and 110B are maximized, and if the detected temperature is less than the threshold value, the outputs of the fans 110A and 110B are reduced below the maximum. A plurality of threshold values may be prepared, and control may be performed in a plurality of stages so that the fan output increases as the temperature increases.

  The gas forming the air curtain discharged from the back surface of the first housing B1 is introduced into the second housing B2 arranged on the back surface side of the first housing B1 for cooling the control unit 200. An opening 320 for introduction is provided on the wall surface of the second housing B2 facing the first housing B1.

  One or more control boards 300 and one or more power supplies 310 constituting the control unit 200 described above are arranged inside the second housing B2. Both the control board and power supply are large heat sources. In addition, a fan 321 for exhausting heat in the housing is provided at the outlet of the second housing. Air introduced from the opening 320 is blown onto the surface of the control substrate 300 to cool the substrate surface. Inside the second housing B2, the heat generated by the control board 300 and the power source 310 is exhausted by the fan 321. The air discharged from the first housing and introduced into the second housing B2 is higher than the ambient temperature, but is sufficient to cool the control board and the power supply that become extremely hot.

  According to this embodiment, it is possible to suppress the influence of various heat sources of the printing apparatus from affecting the printing unit and to realize continuous and high-quality printing. The large heat generating parts inside the first housing B1 are the drying part 8 and the humidification generating part 20, and these heats are suppressed from being transmitted to the printing part 4 by the air curtain. In addition, the control unit 200, which is another large heat generation unit of the printing apparatus, and the power source are housed in a second casing different from the first casing B1, and the second casing is utilized using the airflow of the air curtain. By cooling the inside of the printer, heat is prevented from being transmitted to the print unit 4.

  Note that the back surface of the first housing B1 or the entire surface of the second housing does not necessarily have to be a wall surface of the housing, and may have a form in which the wall surface is omitted. If at least one of the back surface of the first housing B1 and the wall surface of the front surface of the second housing B2 is present, it becomes a partition between the two housings and reduces the heat transmitted from the control unit to the printing unit. Because you can.

  Further, the effect can be obtained by blocking between at least one of the drying unit 8 and the humidification generating unit 20 and the print unit 4 with an air curtain. Further, if there is a heat generation part in addition to the drying part 8 and the humidification generation part 20, the space between the heat generation part and the printing part 4 may be blocked by an air curtain.

  The advantage of having an air curtain system will be explained. FIG. 6 is a graph plotting the ambient temperature of the print unit 4 (detection output of the temperature sensor 120) with the continuous operation time of the apparatus. The broken line in the graph shows the change in temperature change when no air curtain is formed. The temperature continues to rise with the operating time and exceeds the allowable temperature of the print unit 4. On the other hand, the solid line in the graph is a temperature change when the air curtain is formed, and is maintained at a substantially constant temperature after a certain time from the start of operation. That is, it can be seen that by providing the air curtain system, high-quality printing can be stably performed even when the operation time is long.

4 Print section 8 Drying section (heat generation section)
14 Print head 20 Humidification generating part (heat generating part)
DESCRIPTION OF SYMBOLS 100 Introduction part 110 Discharge part 120 Temperature sensor 200 Control part 300 Control board 310 Power supply 320 Opening 321 Fan AC Air curtain AF Flow of humidification gas B1 1st housing | casing B2 2nd housing | casing

Claims (8)

A print unit that includes an inkjet printhead and prints on a conveyed sheet;
A drying unit including a heater and drying the printed sheet;
A generator that includes a heater and generates humidified gas;
A supply unit for supplying the humidified gas to the print unit;
A first housing in which the printing unit, the drying unit, the generation unit, and the supply unit are accommodated;
A control unit for controlling the device;
A second housing different from the first housing in which at least a part of the control unit is accommodated;
Means for forming an air curtain in a space between the print unit and at least one of the drying unit and the generation unit inside the first housing;
And the gas forming the air curtain discharged from the first casing is introduced into the second casing for cooling the control unit.   In the first housing, the drying unit and the generation unit are disposed below the printing unit, and the direction in which the air curtain flows is a direction that intersects the direction in which the sheet is conveyed. The printing apparatus according to claim 1, wherein the printing apparatus is characterized.   The printing apparatus according to claim 1, wherein the humidified gas flows in the space along a direction in which the sheet is conveyed, and the air curtain flows so as not to obstruct the flow of the humidified gas. .   The means for forming the air curtain has a fan for introducing outside air from an opening provided in the front surface of the first housing, and the air curtain flows gas from the front surface to the back surface of the first housing. The printing apparatus according to claim 1, wherein the printing apparatus is a printer.   5. The apparatus according to claim 1, further comprising: a detector that detects a temperature in the print unit; and a unit that adjusts a flow of the air curtain according to detection by the detector. The printing apparatus as described. A print unit that includes an inkjet printhead and prints on a conveyed sheet;
A heat generating part including a heater;
A first housing that accommodates the print unit and the heat generation unit;
A control unit for controlling the device;
A second housing different from the first housing in which at least a part of the control unit is accommodated;
Means for forming an air curtain in a space between the heat generation part and the print part inside the first housing;
The gas forming the air curtain is introduced into the second housing for cooling the control unit. A print unit that includes an inkjet printhead and prints on a conveyed sheet;
A generator that includes a heater and generates humidified gas;
A supply unit for supplying the humidified gas to the print unit;
A housing in which the print unit, the generation unit, and the supply unit are housed;
Means for forming an air curtain in a space between the generating unit and the printing unit inside the housing;
A printing apparatus comprising: A print unit that includes an inkjet printhead and prints on a conveyed sheet;
A drying unit including a heater and drying the printed sheet;
A housing in which the printing unit and the drying unit are housed;
Means for forming an air curtain in a space between the drying unit and the printing unit inside the housing;
A printing apparatus comprising:

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