JP3597487B2 - Image forming device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus capable of performing monochrome printing by an electrophotographic system and color printing by an inkjet system.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as an image forming apparatus for obtaining a color image, there are mainly an electrophotographic method (toner type) and an inkjet method (ink type). However, these two methods have the following advantages and disadvantages, and there is no method for effectively using both advantages.
[0003]
That is, although the electrophotographic method has the advantage that printing can be performed at high speed, the use of toner and a heat fixing mechanism has the disadvantage that color reproducibility depends on the transparency of the toner and the hue changes depending on the fixing temperature. there were.
[0004]
Further, since the toner is used, there is a disadvantage that unevenness of the toner layer thickness occurs on the recording paper. In addition, although the ink jet printer system is excellent in color reproducibility of the ink, it requires a long time to dry the ink, and printing cannot be performed at high speed.
[0005]
By the way, it is well known that generally printed image information has a low printing ratio of full color for expressing color, and "partial color" in which a seal, an illustration, a graph, or the like is inserted into a document or the like.
[0006]
In order to take advantage of such marketability and the advantages of both types, an electrophotographic system and an ink jet printer are installed in one device, black and white printing is performed in the electrophotographic portion, and color printing is performed in the ink jet printer system. A method that effectively utilizes the advantages of has been proposed.
[0007]
For example, Japanese Patent Application Laid-Open No. 8-95463 proposes an image forming apparatus in which printing by an ink jet method is performed after printing by an electrophotographic method. There has been proposed a technique for keeping the scourge state of ink constant.
[0008]
[Problems to be solved by the invention]
However, according to the above-mentioned conventional technique (Japanese Patent Laid-Open No. 8-95463), printing on paper is limited to one-sided printing, and in recent years, the other function of the one-sided printing function / two-sided printing function required for printing must be satisfied. Can not.
[0009]
In addition, since the electrophotographic method and the ink jet method are processed on one transport path, the distance from the fixing unit of the electrophotographic method to the printing unit of the ink jet method becomes unnecessarily long. (Depending on the printing speed of the ink jet system).
[0010]
The present invention has been made in view of such circumstances, and has as its object to provide an image forming apparatus capable of performing a double-sided printing method capable of printing at substantially uniform speed regardless of whether image information is monochrome / color / mixed. .
[0011]
Another object of the present invention is to provide a compact image forming apparatus capable of eliminating the damage to the paper caused by the mixture of the ink jet printing and the electrophotographic printing and shortening the time until the paper is discharged. And
[0012]
[Means for Solving the Problems]
Means for solving the above problems are configured as follows.
[0013]
(1) a paper transport path for guiding the paper stored in the paper cassette to a paper output tray;
An electrophotographic printing unit arranged to print a monochrome image on one printing surface of the paper conveyed through the paper conveyance path,
On the downstream side of the electrophotographic printing section in the paper transport path, an inkjet printing section arranged to perform printing of a color image on the other printing surface of the paper,
At the time of single-sided printing of a monochrome image, the paper discharge roller is disposed at a position where the paper is printed onto a paper discharge tray with the print surface of the paper facing downward,
At the time of double-sided printing of an image in which a monochrome image and a color image are mixed, printing of a monochrome image on the back side of the paper, printing of a color image on the front side of the paper, Upside down The printing of a monochrome image on the front side of the paper and the printing of a color image on the back side of the paper are performed in this order.
[0034]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.
[0035]
(Device configuration and operation)
As shown in FIG. 1, the image forming apparatus according to the present embodiment has a document table 3 made of transparent glass or the like on the upper surface.
[0036]
(Document reading section)
A scanner optical system 4 is arranged below the document table 3. The scanner optical system 4 includes an exposure light source 5 for irradiating a document placed on the document table 3 with light, and a scanner optical system 4 for reflecting light reflected from the document, for example, as indicated by a dashed line in the figure. A plurality of reflecting mirrors 8 leading to a photoelectric conversion element (CCD) 7 disposed on the other side (right side) through an imaging lens 6 inside the imaging lens 6; the imaging lens 6 disposed in an optical path; And
[0037]
(Printing part 1: Electrophotographic method)
First, monochrome image data in a document read by the CCD 7 is subjected to image processing, and a laser scanning unit (hereinafter, referred to as LSU) 11 irradiates a laser beam onto the surface of the photoconductor 12 to form an electrostatic latent image. .
[0038]
The photoreceptor 12 has a drum shape which is driven to rotate in the direction of the arrow. A developing device 13 for developing the latent image into a visible image using toner; a transfer charger 14 for transferring the toner image on the photoconductor 12 to a sheet; a cleaning device (not shown) for removing residual toner on the surface of the photoconductor; A static eliminator 15 for removing the surface potential, a main charger 16 for charging the photoconductor 12 to a predetermined potential, an LSU 11 for irradiating a laser toward a laser irradiation point of the photoconductor 12, and the like are sequentially provided.
[0039]
The transfer paper P is stored in a paper cassette 17. A half-moon roller 18 for feeding the paper P is disposed at the leading end of the paper cassette 17, and the downstream side (for convenience, the side where the paper P flows out (cassette side) is the upstream side, and the discharge side is the downstream side). Downstream), an idle roller front detection switch (sheet input sensor) 19 for detecting the passage of the sheet P, and the toner image on the photoconductor 12 and the sheet P based on the signal of the idle roller front detection switch 19. An idle roller 20 for positioning, a transfer charger 14 for transferring the toner image on the photoreceptor 12 to the transfer paper P, a fixing roller 21 for fixing the toner image transferred on the paper P by heat, and the fixing roller 21 A fixing paper detection switch (not shown) for detecting that the paper P has passed, a paper discharge detection switch (not shown) for detecting that the transfer paper has passed in front of the paper discharge roller 36, and discharging of the paper P The sheet discharge rollers 36 to have been disposed.
[0040]
(Printing unit 2: Inkjet method)
The color image data in the document read by the CCD 7 is subjected to image processing, and one sheet P is conveyed by the half-moon roller 18. The paper P is conveyed to the ink jet printing unit 2 via the idle roller 20, the transfer charger 14, and the fixing roller 21. After the paper P is stopped by the transport rollers 34, the paper is transported by adjusting the leading edge of the image information and the leading edge of the paper, and reaches the printing unit 2.
[0041]
The printing unit 2 includes an ink carriage 24 on which an ink head is mounted, and an ink carriage holding shaft (not shown) arranged to facilitate scanning thereof. Is discharged onto the sheet P, and image information is recorded. At this time, the paper P is temporarily stopped, and when the ink carriage 24 completes scanning of one line (one direction), the recording paper corresponding to a plurality of ink nozzles of the ink head is conveyed.
[0042]
As described above, in the printing unit 2, the image information is written on the paper P by performing the above-described processing continuously in accordance with the image information. The printed paper P is discharged to a paper discharge tray (not shown) via a paper discharge roller 36 and provided to the user as a printed matter. 26 is a sub-transport path, and 27 is a manual feed tray.
[0043]
Next, the printing process will be described with reference to FIGS.
[0044]
First, the configuration of the printing units 1 and 2 in the MFP will be described in detail with reference to FIG. As shown in the figure, a sheet conveyed from a sheet feeding unit such as a sheet feeding cassette (not shown) is carried into a printing unit by an idle roller (not shown) with the timing of the leading edge of the image and the leading edge of the sheet adjusted.
[0045]
The printing unit in the present embodiment has both an electrophotographic printing unit 1 and an inkjet printing unit 2, and both printing units 1 and 2 are connected via a paper transport path 31. The paper transport path 31 is provided with a reversing switching claw 32 for reversing the paper (used for ink-jet printing, used for double-sided printing), and uses the sub-transport path 26. Will be described later.
[0046]
Each of the transport rollers 34, 35, and 36 disposed on a transport path from a fixing unit (fixing roller) 21 including an electrophotographic heating roller 211 and a pressure roller 212 to a discharge tray 33 includes: The driving roller 341 # and the driven roller 342 # are constituted, and the driven rollers 342, 352, 362 are formed by star rollers. The reason why a star roller having a small contact area with the sheet is used as the driven roller 342 # is to reduce blurring of the printing surface of the sheet printed on the platen 37 by the ink jet method.
[0047]
Next, the outline of the original reading step and the printing step will be described with reference to the flowcharts of FIGS. 3 and 4. For the original reading step in the original fixing method, see the description of the configuration and operation of the above-described apparatus. The document moving method will be described later in detail (Embodiment 2).
[0048]
In the flowcharts of FIGS. 3 and 4, when a print request (STEP 301) is made, the apparatus determines whether the requested document is a single-sided document (STEP 302) or a double-sided document (STEP 303). At this time, if it is determined that the original is a single-sided original, the original reading unit of the apparatus reads the original (STEP 304), and inputs the read image information to the image information storage memory M1 in the control unit (not shown) of the apparatus (STEP 305). ). The input image information is subjected to image processing in the control unit (STEP 306).
[0049]
After the original determined to be a double-sided original in STEP 303 is read by the reading unit of the apparatus in the same manner as the single-sided original (STEP 307), the front side image information is stored in a memory M1 for storing image information of a control unit (not shown) of the apparatus. Then, the back side image information is input to the image information storage memory M2 (STEP 308). The input image information of the front and back sides is subjected to image processing in the control unit as in the case of the one-sided original (STEP 309).
[0050]
As described above, the image information on which the image processing for printing has been performed shifts to printing. During such processing, the input image information is a monochrome original (STEP 310), a color original (STEP 311), or a monochrome original. A determination is made as to whether or not the document is a mixture of black and white (STEP 312), and printing processes (STEP 313, STEP 314, STEP 315) are performed in accordance with the determination, and the printed matter is provided to the user.
[0051]
(Embodiment 1)
Regarding the image information, there are three cases: (1): when the image information is a monochrome document, (2): when the image information is a color document, and (3): when the image information is a mixture of monochrome and color documents. However, in the present embodiment, the case of (3) will be described in detail. That is, the printing process when the image information in STEP 315 (of FIG. 4) in the above description of the printing process is a monochrome / color mixed original will be described below with reference to the flowcharts shown in FIGS.
[0052]
First, when it is determined that the original is a mixed monochrome / color original, both the electrophotographic and inkjet printing units 1 and 2 operate. The apparatus first determines whether to perform single-sided printing (STEP 601) or double-sided printing (STEP 602).
[0053]
In this determination, when it is determined that one-sided printing is to be performed, the image information of the monochrome portion of the image information stored in the memory M1 in the image information stored in the control unit of the above-described apparatus is called and the photosensitive member 12 is read. After writing as an electrostatic latent image thereon, it is visualized using a developer in a developing tank, and then the developer visualized on the photoconductor 12 is transferred onto the paper P by the transfer charger 14. (STEP 603, STEP 604, STEP 605).
[0054]
The unfixed developer on the transferred sheet adheres to the sheet by the heat and pressure in the fixing process (STEP 606), and thereafter (the sheet passes through the sheet transport path 31 and is discharged to the discharge tray 33 by the discharge rollers 36). ), The rear end of the sheet is chucked (STEP 608), and an operation of switching back the sheet (conveyance in the reverse direction) is performed (STEP 610).
[0055]
At this time, the paper is smoothly introduced into the sub-transport path 26 of the apparatus by turning the switching claw 32 for reversal in the direction B in FIG. 2 (STEP 610). The introduced paper is conveyed to the paper discharge roller 36 via the idle roller 20, the transfer charger 14, and the fixing unit 21 (STEP 610 to STEP 611), and stops while the rear end of the paper is chucked (STEP 611). This completes the sheet reversal.
[0056]
Thereafter, the sheet is switched back, and stops in a state where the leading end of the sheet is chucked by the transport roller 34 (341 + 342) in FIG. At this time, the switching claw 32 for inversion is switched from the direction A to the direction B, thereby preventing the rear end of the sheet from entering the fixing unit 21 (STEP 612).
[0057]
At the timing when the leading edge of the sheet set in this way matches the leading edge of the image of the color image information transmitted to the ink head, the transport and printing of the sheet are performed (STEP 613). At this time, when a serial ink head that operates on the paper width is used as the ink jet type ink head, the paper is conveyed in a predetermined range (the number of nozzles of the ink head). It is necessary to determine whether or not it is (STEP 614). After printing all the image information on one side in this manner, the paper is discharged to the paper discharge tray 33 (STEP 615).
[0058]
As described above, at the time of single-sided printing, by temporarily reversing the sheet using the sub-conveying path 26 which is not a normal conveying path, printing of monochrome and color mixed information on one conveyed side (one side). Becomes possible.
[0059]
Next, when double-sided printing is selected in STEP 602, the image information of the monochrome portion of the back side image information stored in the memory M2 is called, and after the image information is written on the photoconductor 12 as an electrostatic latent image, Then, the image is visualized by using the developer of the developing device 13, and the visualized developer on the photoconductor 12 is transferred onto the sheet by the transfer charger 14 (STEP 616, STEP 617, STEP 618).
[0060]
The unfixed developer on the transferred sheet adheres to the sheet by the heat and pressure in the fixing process (STEP 619), and thereafter (the sheet passing through the sheet transport path 31 is discharged to the sheet discharge tray by the discharge roller 36). Instead, the rear end of the sheet is chucked (STEP 621), thereby completing the printing of the monochrome image on the back surface.
[0061]
Next, processing of the color image of the front surface is performed. That is, when STEP 621 is completed, the image information of the color portion of the surface image information stored in the memory M1 in the image information stored in the control unit of the apparatus is called and transmitted to the ink head (STEP 622).
[0062]
After the back end of the sheet is switched back to the transport rollers 35 (351 + 352) (STEP 623), the sheet is set at the timing when the leading end of the set sheet coincides with the leading end of the color image information transmitted to the ink head. Is carried out and printing is performed (STEP 624).
[0063]
At this time, when a serial ink head that operates on the paper width is used as the ink jet type ink head, the paper is conveyed in a predetermined range (the number of nozzles of the ink head). It is necessary to determine whether or not it is (STEP 625). After printing all the surface color image information in this manner, the sheet is guided to the idle roller 20 via the sub-transport path 26 (STEP 626).
[0064]
When the paper reaches the idle roller 20, the image information of the monochrome portion of the surface image information stored in the memory M1 is called, and after writing as an electrostatic latent image on the photoconductor 12, the developer in the developing device 13 is removed. Then, the developer that has been visualized by the transfer charger 14 and is visualized by the transfer charger 14 is transferred onto a sheet (STEP 627, STEP 628, STEP 629).
[0065]
The unfixed developer on the transferred sheet adheres to the sheet by the heat and pressure of the fixing process (STEP 630), and then (the sheet is discharged to the discharge tray 33 by passing through the transport path and by the discharge roller 36). No), the rear end of the sheet is chucked (STEP 632). Thereby, printing of the monochrome image on the front surface is completed.
[0066]
Next, processing of the color image on the back surface is performed. That is, when STEP 632 is completed, the image information of the color portion of the back image information stored in the memory M2 of the control unit of the apparatus is called and transmitted to the ink head (STEP 633).
[0067]
After the leading edge of the paper is switched back to the transport rollers 34 (341 + 342) (STEP 634), the set paper and the transmitted color image information of the ink head are transported and printed at the timing when the leading edge of the paper is aligned with the leading edge of the image. Is performed (STEP 635).
[0068]
At this time, when a serial ink head that operates on the paper width is used for the ink jet type ink head, the paper is conveyed in a predetermined range (the number of nozzles of the ink head). It is necessary to determine whether or not it is (STEP 636). After printing all the surface color image information in this manner, the paper is discharged to the paper discharge tray 33 (STEP 615).
[0069]
By printing the image information as described above, the printing of the monochrome / color / mixed document of the image information is completed. With such a configuration, it is possible to reduce the size of the apparatus and speed up printing.
[0070]
As described above, in an apparatus having both the electrophotographic system and the ink jet system, a design which sufficiently pays attention to the distance between the fixing unit 21 of the electrophotographic system and the printing unit 2 of the ink jet system is required. Needed.
[0071]
That is, if a design is made such that the rear end of the paper reaches the fixing unit 21 of the electrophotographic system during printing by the ink jet system, the paper is excessively fixed by the fixing unit 21 during the printing by the ink jet system, and Such a situation must be avoided since high temperature offset of the agent and discoloration of the paper may occur.
[0072]
Therefore, when printing is performed by the inkjet method as in the present embodiment, the sheet is always transported to the paper discharge roller 36, and then the paper is guided to the sub-transport path 26 using the switchback function. By using the method, it is possible to solve the problem in the fixing unit 21 and to reduce the size of the apparatus.
[0073]
Further, by effectively using the radiant heat of the electrophotographic fixing unit 21, for example, the fixing cover 213 (see FIG. 2) covering the heating roller 211 of the fixing unit 21 can be brought close to or close to the paper transport path guide plate 311. By adopting a configuration in which the guide plate is also used as the fixing cover 213 or the like, the drying of the printed ink jet type ink is promoted, or the paper before printing is dried in advance to absorb the ink. And the drying property can be improved.
[0074]
(Embodiment 2)
In the present embodiment, the movement of the ink carriage 24 to an arrangement position (stop position) that can be variably selected and set will be described below with reference to FIG.
[0075]
FIG. 9 is a schematic cross-sectional view of an image forming apparatus having a sub-conveying path 26 capable of a single-sided printing / double-sided printing function, and a configuration for enabling color printing / monochrome printing, that is, an ink carriage 24 (241 to 244). ), An electrophotographic fixing heat roller 211, a CRU (removable and replaceable photoconductor unit) 12, and an LSU 11. FIG. In the drawing, reference numerals 241 to 244 indicate the respective positions of the ink carriage 24. Although not shown in FIG. 9, an electrophotographic transfer charger and a developer unit are also provided.
[0076]
First, in the present embodiment, a case will be described in which the ink carriage 24 is moved according to the print paper size. That is, a configuration will be described in which the arrangement position of the ink carriage 24 used for printing by the ink jet system can be variably selected and set according to the printing paper size or printing conditions.
[0077]
When performing printing by inkjet, it is necessary to perform printing with the rear end of the paper completely passing through the fixing heat roller 211 regardless of the paper size, for the above-described reason.
[0078]
Therefore, for example, the position of the leading edge of the paper when the trailing edge of the A3-size paper passes through the fixing heat roller 211 (that is, the position of the ink carriage for enabling ink printing) is indicated by reference numeral 241 in FIG. The position of the ink carriage 242 in the drawing is such that the ink carriage can pass through the fixing heat roller 211 so that ink can be printed. Then, it is assumed that the initial position (home position) of the ink carriage 24 is at the position 244 in the figure, and that the ink carriage 24 is at the position 244 in the standby state.
[0079]
FIG. 10 shows a control system for performing printing control, paper conveyance control, and the like by the image forming apparatus. In the figure, reference numeral 7 denotes a CCD, which can read a monochrome original and a color original. 38, an A / D converter for digitally converting image information from the CCD 7, 39, an image processing ASIC for performing image processing on input image information, 40, a central processing unit (CPU) for performing various controls and monitoring of the image forming apparatus The operation and control of the ink carriage 24, the LSU 11, and various loads are performed.
[0080]
Reference numeral 41 denotes an ink carriage control system for performing ink head control and movable control of the ink carriage 24, reference numeral 42 denotes an LSU control system, reference numeral 43 denotes a control system for various loads such as various sensors and transport systems, and reference numeral 44 denotes a simplified operation panel unit. Is shown.
[0081]
For example, when a print request is issued from the standby state, the CPU 40 recognizes the paper size by the control system 43 of various loads. As a result of the recognition, for example, if the paper size is A3 size, the CPU 40 controls the ink carriage control system 41 so as to move the ink carriage 24 from the position 244 in FIG.
[0082]
For example, if the paper size is A4 size, the CPU 40 controls the ink carriage 24 to move to the position 242 in FIG. Here, if there is a paper size sensor in the paper cassette 17, the ink carriage 24 is made to move simultaneously with the print request, and there is no paper size sensor in the paper cassette 17, for example, the paper input sensor in FIG. In the case of detecting the paper size at the ON / OFF time of 19, the CPU 40 calculates the paper size after the leading edge of the paper turns on the paper input sensor 17 and the rear end of the paper turns off the paper input sensor 17. Then, the ink carriage 24 is moved to an optimum position based on the calculation result.
[0083]
Here, with respect to the movement and the stop position of the ink carriage 24, there are some devices that are fixed positions set in advance (for example, A4 / A3 / B4 / B5 / corresponding positions of each inch size), and the ON of the paper input sensor 17 Needless to say, an apparatus that optimizes the position of the ink carriage 24 by linearly moving the position of the ink carriage 24 steplessly according to the paper size calculated from the / OFF time is also conceivable.
[0084]
Further, the ink carriage 24 can be moved to a position 243 in FIG. 9 as an arrangement position. In other words, the ink printing may be performed when the paper having the fixed surface once passes through the transport roller (first paper discharge roller) 34 and is directed to the sub-transport path 26 for the reverse side printing by the switchback function. It is possible.
[0085]
After moving the ink carriage 24 to the optimal arrangement position according to the paper size, the CPU 40 and the image processing ASIC 39 perform printing control using ink. The CPU 40 also monitors the remaining amount of ink. When the remaining amount of ink becomes insufficient for image formation, the CPU 40 displays the ink replacement on the operation panel unit 44 and sets the ink carriage 24 in FIG. 244 is arranged so as to facilitate ink replacement. The position of the 244 is a position where the user can easily attach / detach / replace the ink tank.
[0086]
(Embodiment 3)
Next, the present embodiment relates to a structure / control means for moving the ink carriage 24. FIG. 11 is a schematic plan view of a drive system of the ink carriage 24 for explaining a means for moving the ink carriage 24. In the figure, reference numerals 241 to 244 denote the respective positions of the ink carriage 24, sensors 51 (511 to 514) are photosensors provided at the respective positions 241 to 244, and a motor 52 drives the ink carriage 24. The driving belt 53 is a timing belt for transmitting the driving force from the driving motor 52 to the ink carriage 24, and the rotary volume 54 is a volume resistor for detecting the rotation angle of the driving motor 52.
[0087]
For example, when the CPU 40 moves from the initial position (home position) 244 to the position 241 of the ink carriage 24 based on the detection result of the paper size, the CPU 40 controls the drive motor so as to move the ink carriage 24 from 244 to 241. 52 is controlled. At this time, an actuator (not shown) is provided in the ink carriage 24, and the actuator shields the photo sensor 511 at the position 241 in the figure.
[0088]
Then, the CPU 40 recognizes the result of the light shielding, stops the motor 52 in order to stop the ink carriage 24 at the position of the 241, and thereby moves and sets the ink carriage 24 to the position of the 241. Note that the CPU 40 recognizes the current position of the ink carriage 24 and, for example, if the ink carriage 24 is located at the position 244 in the drawing, counts the light shielding of the photo sensor 51 at each arrangement position up to 241 before arranging it. It stops after recognizing the light shielding at the position 241.
[0089]
For example, if the ink carriage 24 is currently at the position 242 and moves to the position 244, the drive motor 52 is rotated in the direction toward the position 244, and the CPU 40 controls the light sensor 241 to block light from the photo sensor 511. After the counting, the ink carriage 24 is stopped by recognizing the light blocking of the photo sensor 514 at 244. Here, the drive motor 52 can be realized by a stepping motor or a DC motor.
[0090]
Further, if the stop position of the ink carriage 24 can be set steplessly, for example, a rotary volume 54 for detecting the rotation angle of the drive motor shown in the drawing is provided, and the position of the ink carriage 24 is set to the resistance value of the rotary volume 54. Thus, the CPU 40 can perform position detection based on the value obtained by converting the voltage from the resistance value, and stop and drive the drive motor 52 according to each stop condition.
[0091]
Of course, this can be achieved not only by analog control by a DC motor, but also by controlling the motor almost steplessly, for example, by counting the number of steps by the CPU 40 using a stepping motor, and controlling the ink carriage position. . In that case, the photo sensor 51 can be omitted.
[0092]
In FIG. 11, reference numerals 55 and 55 denote rails for driving the ink carriage 24 in the paper transport direction, and reference numeral 56 denotes a shaft for moving the ink carriage 24 in the line (main scanning) direction. 53, the rail 55 and the shaft 56 are connected so that they can operate smoothly.
[0093]
【The invention's effect】
As apparent from the above description, the present invention has the following effects.
[0094]
According to the first aspect, the arrangement position (stop position) of the ink carriage can be set to an appropriate position in accordance with the printing paper size or printing conditions, so that deterioration of printing quality can be avoided and paper discharge can be prevented. This makes it possible to optimize the time required for printing, and to print at a substantially uniform speed regardless of whether the image information is monochrome / color / mixed. And the apparatus can be made compact. In addition, the replacement / removal work of the ink carriage is facilitated.
[0095]
According to the second aspect, since the ink carriage can be moved to an appropriate arrangement position (stop position) according to the size of the printing paper, damage to the paper caused by a mixture of the ink jet printing and the electrophotographic printing can be prevented. In addition, the time required for paper discharge can be reduced, and the apparatus can be made more compact.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of the main part.
FIG. 3 is a part of a flowchart for explaining the original reading step and the printing step.
FIG. 4 is the remainder of the flowchart.
FIG. 5 is a part of a flowchart for describing a printing process when the image information is a mixed monochrome / color original.
FIG. 6 is another part of the flowchart.
FIG. 7 is still another part of the flowchart.
FIG. 8 is the remainder of the flowchart.
FIG. 9 is an explanatory diagram of an arrangement position (stop position) of the ink carriage.
FIG. 10 is a control system diagram.
FIG. 11 is a schematic plan view of a drive system of the ink carriage.
[Explanation of symbols]
24-ink carriage
241-244-Arrangement position (stop position)
21-fixing roller
34-36-transport roller
37-printing platen
52-drive source
53-endless belt

Claims (1)

A paper transport path that guides the paper stored in the paper cassette to the paper output tray,
An electrophotographic printing unit arranged to print a monochrome image on one printing surface of the paper conveyed through the paper conveyance path,
On the downstream side of the electrophotographic printing section in the paper transport path, an inkjet printing section arranged to perform printing of a color image on the other printing surface of the paper,
At the time of single-sided printing of a monochrome image, the paper discharge roller is disposed at a position where the paper is printed onto a paper discharge tray with the print surface of the paper facing downward,
In duplex printing of an image in which a monochrome image and a color image are mixed, printing of a monochrome image on the back of the paper, printing of a color image on the front of the paper, inversion of the paper, printing of a monochrome image on the front of the paper, and a color image on the back of the paper An image forming apparatus for performing printing in this order.

Images