JP2018001502A - Liquid discharge unit, device for discharging liquid and image formation control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge unit which prevents sheet rubbing of a liquid discharge head.SOLUTION: A liquid discharge unit includes: a carriage 100 which has a recording head 118; a carriage drive unit which drives the carriage in the main-scanning direction; a sheet feeding unit which has a platen facing the main-scanning direction of the carriage and feeds a printing medium 108 to a section between the carriage and the platen; a gap switching unit which adjusts the gap between the recording head 118 and the printing medium 108; and a printing control unit which controls drive of the carriage drive unit, sheet feeding unit and gap switching unit. The printing control unit controls drive of the carriage drive unit in accordance with the thickness of the printing medium fed from the sheet feeding unit at the printing to the printing medium, and moves the carriage to the carriage ascending position or carriage descending position provided outside the sheet feeding path of the printing medium.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid ejection unit, an apparatus for ejecting liquid, and an image formation control method.

  In an apparatus for ejecting liquid, such as an ink jet printer, the distance between the liquid ejection head and the print medium varies depending on the thickness of the print medium such as recording paper used for printing. In order to perform clear printing, it is desirable to keep the distance between the liquid discharge head and the printing medium constant regardless of the thickness of the printing medium to be used.

  2. Description of the Related Art Conventionally, as an apparatus for ejecting liquid, there has been proposed an apparatus that adjusts a distance between a liquid ejection head and a platen automatically or by a user operation according to the thickness of a recording sheet to be used. In addition, when the recording paper absorbs ink and swells, so-called `` paper rubbing '' that the recording paper comes into contact with the liquid ejection head is likely to occur, and according to paper information such as the type and size of the recording paper, A device that automatically raises and lowers the liquid discharge head with respect to the platen has also been proposed (see, for example, Patent Document 1).

  However, conventional liquid ejection devices adjust the recording paper feed timing according to the technology to retreat the liquid ejection head from the recording paper feed position when the liquid ejection head is raised or lowered, and the liquid ejection head elevation timing. Since no consideration is given to the technology used, it is practically difficult to completely prevent paper rubbing, and there is room for improvement in this respect.

  The present invention has been made to solve such problems of the prior art, and an object thereof is to prevent paper rubbing of a liquid discharge head.

  In order to solve the above problems, according to one embodiment of the present invention, a carriage including a recording head, a carriage driving unit that drives the carriage in a main scanning direction, and a platen are provided opposite to the main scanning direction of the carriage. A paper feed unit that feeds a print medium between the carriage and the platen, a gap switching unit that adjusts a gap between the recording head and the print medium, the carriage drive unit, and the paper feed unit And a print control unit that controls driving of the gap switching unit, and the print control unit is configured to print the carriage according to the thickness of the print medium fed from the paper feed unit when printing on the print medium. The drive of the drive unit is controlled, and the carriage is moved to a carriage ascending position or a carriage descending position provided outside the print medium feeding path. That.

  According to the present invention, paper rubbing of the liquid discharge head can be prevented.

It is a top view which shows schematic structure of the liquid discharge unit with which the inkjet printer which concerns on embodiment is equipped. 1 is a functional block diagram of a recording control device that controls an inkjet printer and peripheral devices thereof according to an embodiment. 5 is a flowchart illustrating a procedure of gap setting processing executed by a print control unit provided in the recording control apparatus according to the embodiment. It is a side view of the liquid discharge unit concerning an embodiment. It is a perspective view of the liquid discharge unit which concerns on embodiment. It is a front view of the liquid discharge unit concerning an embodiment. FIG. 6 is a schematic diagram illustrating a positional relationship between a recording sheet conveyance path and a carriage lowering position in the liquid ejection unit according to the embodiment. FIG. 6 is a schematic diagram illustrating a positional relationship between a recording sheet conveyance path and a carriage rising position in the liquid ejection unit according to the embodiment. 6 is a flowchart illustrating a first example of a control method for recording paper feeding timing and carriage raising timing in the inkjet printer according to the embodiment. 6 is a flowchart illustrating a second example of a method for controlling recording paper feed timing and carriage ascent timing in the inkjet printer according to the embodiment. FIG. 4 is a diagram illustrating a relationship between a recording paper feed timing and a main scanning range of a recording head in the inkjet printer according to the embodiment. 10 is a flowchart illustrating a third example of a method for controlling recording paper feed timing and carriage ascent timing in the inkjet printer according to the embodiment. It is a figure which shows the printing start direction in the case of printing a cardboard with the inkjet printer which concerns on embodiment. It is a figure which shows the printing start direction in the case of printing a standard paper with the inkjet printer which concerns on embodiment.

  Hereinafter, an embodiment of a liquid ejection unit, an apparatus for ejecting liquid, and an image formation control method according to the present invention will be described with reference to the drawings. In the embodiments described below, a liquid discharge unit provided in an ink jet printer will be described as an example, but the present invention can also be applied to an apparatus for discharging liquid other than an ink jet printer and a liquid discharge unit provided in the apparatus. .

  As shown in FIG. 1, in the liquid ejection unit according to the embodiment, the carriage 100 is held by a slide rail 104 made of sheet metal. The carriage 100 is connected to a timing belt 102 wound between a driving pulley 106 and a driven pulley 107 that are rotationally driven by a main scanning motor 105, and the timing belt is driven by rotating the main scanning motor 105. Through 102, the recording paper 108 is moved in the main scanning direction which is set along the surface of the recording paper 108 and in a direction orthogonal to the feeding direction of the recording paper 108. Accordingly, the carriage 100, the timing belt 102, the main scanning motor 105, the driving pulley 106, and the driven pulley 107 constitute a carriage driving unit that moves the carriage 100 in the main scanning direction.

  For example, four liquid ejection heads 118Y, 118C, 118M, and 118K that eject ink droplets (liquid) of four colors of yellow (Y), cyan (C), magenta (M), and black (K) are disposed on the carriage 100, for example. A recording head 118 is mounted. The recording head 118 is formed with nozzle hole arrays for ejecting ink of each color on the nozzle hole surface. The nozzle hole arrays are arranged in the main scanning direction, and are arranged on the carriage 100 so as to eject ink droplets downward. Is set. In the present embodiment, the case where independent liquid ejection heads 118Y, 118C, 118M, and 118K are used for each color will be described. However, one or a plurality of nozzle hole arrays that eject ink droplets of each color are used. The liquid ejection head may be provided. Further, the number of liquid ejection heads and the arrangement of the ink ejection ports can be changed as appropriate.

  The liquid discharge heads 118Y, 118C, 118M, and 118K include a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change due to liquid film boiling using an electrothermal transducer such as a heating resistor, and a metal phase due to a temperature change. For example, a shape memory alloy actuator using change, an electrostatic actuator using electrostatic force, or the like provided as pressure generating means for generating pressure for discharging a liquid can be applied.

  The carriage 100 is provided with an encoder scale 103 formed with slits along the main scanning direction, and the carriage 100 is provided with an encoder sensor 117 for detecting the slit of the encoder scale 103. The encoder scale 103 and the encoder sensor 117 constitute a linear encoder that detects the position of the carriage 100 in the main scanning direction.

  In addition, a platen is provided in the vicinity of the carriage 100 so as to face the main scanning direction of the carriage 100, and a paper feeding unit 130 for feeding the recording paper 108 as a printing medium between the recording head 118 and the platen. Provided. The paper supply unit 130 includes a conveyance belt 101 that is a conveyance unit for electrostatically attracting the recording paper 108 to a position facing the recording head 118. The conveyor belt 101 is wound around a conveyor roller 109 and a tension roller 110, and a conveyor roller pulley 113 is coaxially fixed to the conveyor roller 109. Further, a timing belt 114 is wound between the conveyance roller pulley 113 and the conveyance drive pulley 112 that is rotationally driven by the sub-scanning motor 111.

  Therefore, the conveyance belt 101 rotates along the sub-scanning motor 111 to move along the sheet surface of the recording sheet 108 and the recording sheet 108 via the conveyance driving pulley 112, the timing belt 114, the conveyance roller pulley 113, and the conveyance roller 109. Driven in the sub-scanning direction set in the direction along the paper feeding direction.

  A wheel encoder 115 having a slit is coaxially fixed to the conveyor belt 101, and an encoder sensor 116 for detecting the slit of the wheel encoder 115 is provided on the side plate 131 (see FIG. 5) of the paper feeding unit 130. ing. These wheel encoder 115 and encoder sensor 116 constitute a wheel encoder that detects the position of the conveyance belt 101 in the sub-scanning direction. The conveyance belt 101 is an endless belt, and is configured to wrap around the conveyance roller 109 and the tension roller 110 so as to go around in the sub-scanning direction, and is charged (charged) by a charging roller (not shown) while moving around. Is done.

  As the structure of the conveyor belt 101, a single-layer belt or a multilayer belt having two or more layers can be applied. However, in the case of a single-layer belt, the entire layer is preferably formed of an insulating material because it contacts the recording paper 108 and the charging roller. In the case of a multilayer belt, the side that contacts the recording paper 108 and the charging roller is preferably formed of an insulating layer, and the side that does not contact the recording paper and the charging roller is preferably formed of a conductive layer.

  Next, with reference to FIG. 2, functions of the recording control apparatus that controls the ink jet printer including the liquid ejection unit according to the embodiment and its peripheral devices will be described.

  2 includes a printer driver 119, an operation panel 120, a head driver 121 connected to the carriage 100, a main scanning motor 105 connected to the carriage 100, a linear encoder 122, and a charging roller as peripheral devices. 123, a sub-scanning motor 111 connected to the conveyor belt 101, and a wheel encoder 115 are provided.

  The recording control apparatus 200 of this example is responsible for controlling the entire apparatus and a host interface (I / F) 201 for transmitting and receiving data and signals to and from the printer driver 119 on the host side. And a CPU 202 having a control function related to the conveyance operation of the paper 108 and the movement operation of the recording head 118.

  In addition, the recording control device 200 of the present example includes a ROM 203 that stores a program executed by the CPU 202 and other fixed data, a RAM 204 that temporarily stores input image data and the like as storage devices, and a power source of the device is cut off. And an NVRAM 205 as a rewritable non-volatile memory for holding data while the data is being stored.

  Further, the recording control apparatus 200 of this example includes an I / O 206 for inputting detection pulses from the linear encoder 122 and the wheel encoder 115 and detection signals from other various sensors, various signal processing for image data, and the like. And an ASIC 207 for performing arithmetic processing on input / output signals for controlling image processing such as rearrangement and other devices as a whole.

  In addition, the recording control apparatus 200 of the present example generates a drive waveform for driving the recording head 118, and also outputs image data for selectively driving the pressure generating means of the recording head 118 and various data associated therewith to the head driver 121. , A main scanning motor driving unit 209 for driving the main scanning motor 105, an AC bias supplying unit 210 for supplying an AC bias to the charging roller 123, and a sub scanning motor 111. The sub-scanning motor driving unit 211 is provided.

  In addition, an operation panel 120 for inputting and displaying information necessary for the apparatus is connected to the recording control apparatus 200 of this example, and each unit including the operation panel 120 is connected by a common bus. .

  The recording control device 200 in this example includes an information processing device such as a personal computer (PC), an image reading device such as an image scanner, print data generated by a printer driver 119 on the host side such as an imaging device such as a digital camera, and the like. Is received by the host interface (I / F) 201 via a cable or a network, the CPU 202 reads and analyzes the print data in the reception buffer included in the received data, and the ASIC 207 performs necessary image processing, data rearrangement processing, and the like. The data is transferred to the print control unit 208, and the print control unit 208 outputs image data and drive waveforms to the head driver 121 at a required timing.

  The generation of dot pattern data for image output may be performed, for example, by storing font data in the ROM 203, or the image data is developed into bid map data by the printer driver 119 on the host side and transferred to the apparatus. However, the printer driver 119 is used here. The drive waveform generation unit of the print control unit 208 includes a D / A converter and an amplifier that perform D / A conversion on the drive pulse pattern data stored in the ROM 203 and read out by the CPU 202, and includes one drive pulse or a plurality of drive pulses. A drive waveform composed of drive pulses is output to the head driver 121.

  The head driver 121 is a drive pulse that forms a drive waveform provided from the drive waveform generation unit of the print control unit 208 based on image data (dot pattern data) corresponding to one line of the recording head 118 that is input serially. Is selectively applied to the pressure generating means of the recording head 118 to drive the recording head 118.

  Here, the head driver 121 includes, for example, a shift register that inputs serial data that is a clock signal and image data, a latch circuit that latches a register value of the shift register using a latch signal, and an output value of the latch circuit that changes the level. And a switch selection circuit having an analog switch array configuration that is controlled to be turned on / off by the level conversion circuit, and controls on / off of the analog switch array. Thus, a required drive pulse included in the drive waveform is selectively applied to the pressure generating means of the recording head 118.

  Next, a procedure of gap setting processing executed by the print control unit 208 provided in the recording control apparatus 200 according to the embodiment will be described with reference to FIG.

  Ink jet printers often include a mechanism that can change the gap between the recording head 118 and the platen in accordance with the thickness of the recording paper to be printed. In the gap setting (activity) by the print control unit 208 shown in FIG. 3, the process is started by the start node (step S100), and it is determined whether or not a thick paper is selected as the recording paper 108 (step S101). The thick paper refers to a recording paper having a thickness larger than the standard paper recommended by the ink jet printer.

  As a result of the determination, if thick paper is selected, the gap is set to be large (step S104) and then the process proceeds to printing (step S106). If thick paper is not selected, the printer driver 119 continues to use the gap. It is determined whether or not “Large” has been selected (step S102).

  As a result of this determination, if the gap size is selected, the gap size is set (step S104) and then the process proceeds to printing (step S106). If the gap size is not selected, the printer main body is continuously selected. It is determined whether or not the gap size is selected on the operation panel 120 (step S103).

  If the gap size is selected as a result of this determination, the gap size is set (step S104), and then the process proceeds to printing (step S106). If the gap size is not selected, the gap size is set (step S104). After S105), the process proceeds to print execution (step S106). In any case, after printing is executed (step S106), the process is ended by the end node (step S107).

  Next, the configuration of the gap switching unit that switches the gap between the recording head 118 and the platen will be described with reference to FIGS.

  In FIG. 4, an area E <b> 1 shows a rotation stopper that receives a moment due to the weight of the carriage 100. An area E2 indicates a surface portion that positions the carriage 100 in the sub-scanning direction. Furthermore, the surface part which determines the height direction of the area | region E3 and the carriage 100 is shown.

  As shown in FIGS. 4 to 6, the liquid discharge unit according to the embodiment includes a rotating cam member 140 in the region E3. In addition, the ink jet printer has a fixed position for rotating the rotary cam member 140 in a predetermined position by colliding with the rotary cam member 140 when the carriage 100 is moved to a predetermined position in the main scanning direction. A member 150 is provided. The rotary cam member 140 and the fixed pressing member 150 constitute a gap switching unit that switches a gap between the recording head 118 and the platen (printing surface of the recording paper 108).

  That is, in the vicinity of the left and right ends of the rotating cam member 140, as shown in FIGS. 5 and 6, when the carriage 100 is moved to predetermined positions on the right side and the left side in the main scanning direction, it collides with the fixed pressing member 150. In combination, rotating members 141 a and 141 b for converting the pressing force from the fixed pressing member 150 into the rotational force of the rotating cam member 140 are formed.

  Further, two sliding surfaces 142 a and 142 b in which the distance from the rotation center of the rotating cam member 140 changes spirally depending on the circumferential position of the rotating cam member 140 are formed inside the position where the rotation driving member 141 is formed. Has been. As shown in FIG. 4, the sliding surfaces 142a and 142b are in contact with the slide rail 104, and when the rotary cam member 140 rotates, the height position of the recording head 118 with respect to the platen is changed.

  As shown in FIG. 7, in the liquid discharge unit according to the embodiment, when the carriage 100 is moved to a predetermined position in the right direction along the slide rail 104, the fixed pressing member 150 a disposed on the right side of the slide rail 104 rotates. The rotary cam member 140 is rotated in one direction by being abutted with the member 141a, the carriage 100 is lowered, and the gap between the recording head 118 and the platen is reduced.

  On the other hand, as shown in FIG. 8, in the liquid ejection unit according to the embodiment, when the carriage 100 is moved to a predetermined position in the left direction along the slide rail 104, the fixed pressing member disposed on the left side of the slide rail 104. 150b is abutted against the rotating member 141b, the rotating cam member 140 rotates in the other direction, the carriage 100 is raised, and the gap between the recording head 118 and the platen is increased.

  As described above, the liquid ejection unit according to the embodiment is configured to be able to adjust the gap between the recording head 118 and the platen. Therefore, the recording head 118 is independent of the thickness of the recording paper 108 used for printing. The gap between the platen and the platen can be kept constant, and high-quality printing can be performed.

  7 and 8, when the carriage 100 is moved to a predetermined position in the right direction along the slide rail 104, the carriage 100 is lifted up, and the space between the recording head 118 and the platen. When the carriage 100 is moved along the slide rail 104 to a predetermined position in the left direction, the carriage 100 is lowered so that the gap between the recording head 118 and the platen is reduced. You can also.

  Further, as is apparent from FIGS. 7 and 8, the liquid ejection unit according to the embodiment retracts the carriage 100 from the feeding path of the recording paper 108 when switching the gap between the recording head 118 and the platen. Therefore, it is possible to reliably prevent the recording head 118 from being rubbed regardless of the thickness of the recording paper 108 used for printing.

  Next, a method for controlling the feeding timing of the recording paper 108 and the rising timing of the carriage 100 in the inkjet printer according to the embodiment will be described with reference to FIGS.

  FIG. 9 shows a first example of a method for controlling the feeding timing of the recording paper 108 and the raising timing of the carriage 100. As shown in this figure, in the control method of this example, when a thick paper is selected as the recording paper 108, or when a large gap is set by the printer driver 119 or the main body setting, the recording control device 200 of the ink jet printer Before starting the paper feeding, the carriage 100 is moved to the carriage raised position shown in FIGS. Then, feeding of the recording paper 108 is started in a state where the gap between the recording head 118 and the platen is increased, and printing is performed.

  According to the control method of this example, since the recording paper 108 is fed and printing is performed in a state where the gap between the recording head 118 and the platen is large, the recording paper does not contact the recording head 118. Further, it is possible to reliably prevent the recording head 118 from being rubbed.

  FIG. 10 shows a second example of a method for controlling the feeding timing of the recording paper 108 and the raising timing of the carriage 100. As shown in this figure, in the control method of this example, when a thick paper is selected as the recording paper 108, or when a large gap is set by the printer driver 119 or the main body setting, the recording control device 200 of the ink jet printer First, as shown in FIG. 11, the recording paper 108 is fed to just before the movable range of the recording head 118. Thereafter, the recording control device 200 of the ink jet printer moves the carriage 100 to the carriage ascending position shown in FIGS. 7 and 8 before feeding is started. Then, feeding of the recording paper 108 is started in a state where the gap between the recording head 118 and the platen is increased, and printing is performed.

  According to the control method of this example, the same effect as that of the control method according to the first example is obtained, and the recording paper 108 is fed to just before the movable range of the recording head 118 before the carriage 100 is moved to the carriage lift position. Therefore, the printing speed can be increased as compared with the control method according to the first example.

  FIG. 12 shows a third example of a method for controlling the feeding timing of the recording paper 108 and the raising timing of the carriage 100. As shown in this figure, in the control method of this example, when a thick paper is selected as the recording paper 108, or when a large gap is set by the printer driver 119 or the main body setting, the recording control device 200 of the ink jet printer At the same time as the recording paper 108 is fed to just before the movable range of the recording head 118, the carriage 100 is moved to the carriage ascent position. Then, in a state where the gap between the recording head 118 and the platen is increased, the recording paper 108 is fed between the recording head 118 and the platen to perform printing.

  According to the control method of this example, in addition to the same effect as the control method according to the first example, the recording paper 108 is fed to just before the movable range of the recording head 118, and at the same time, the carriage 100 is moved to the carriage rising position. Therefore, the printing speed can be increased as compared with the control method according to the first example.

  Next, a method for controlling the print start direction according to the thickness of the recording paper used for printing will be described with reference to FIGS.

  In the case of printing thick paper using an ink jet printer, as shown in FIG. 13, after the carriage 100 is raised at the carriage raising position provided on the left side of the paper feeding position of the recording paper 108, the recording head Printing is performed by scanning 118 to the right of the paper feed position of the recording paper 108. On the other hand, when printing standard paper using an ink jet printer, the carriage 100 is lowered at the carriage effect position provided to the right of the paper feed position of the recording paper 108 as shown in FIG. After that, the recording head 118 is scanned to the left of the feeding position of the recording paper 108 to perform printing.

  According to the control method of this example, printing can be started immediately from the position where the carriage 100 is raised or lowered regardless of the thickness of the recording paper 108 used for printing. Can be suppressed.

DESCRIPTION OF SYMBOLS 100 Carriage 101 Conveying belt 102,114 Timing belt 103 Encoder scale 104 Slide rail 105 Main scanning motor 106 Drive pulley 107 Driven pulley 108 Recording paper 109 Conveyance roller 110 Tension roller 111 Sub scanning motor 112 Conveyance drive pulley 113 Conveyance roller pulley 115 Wheel encoder 116 117 Encoder sensor 118 Recording head 118Y, 118C, 118M, 118K Liquid ejection head 119 Printer driver 120 Operation panel 121 Head driver 122 Linear encoder 123 Charging roller 130 Paper feed unit 131 Side plate 140 Rotating cam members 141a, 141b Rotating members 142a, 142b Sliding surfaces 150a, 150b Fixed pressing member 200 Inkjet recording Use controller 201 host interface (I / F)
202 CPU
203 ROM
204 RAM
205 NVRAM
206 I / O
207 ASIC
208 Print Control Unit 209 Main Scanning Motor Driving Unit 210 AC Bias Supply Unit 211 Sub Scanning Motor Driving Unit 212 Fixed Push Member 213 Rotating Member

JP 2006-103278 A

Claims (8)

A carriage with a recording head;
A carriage drive unit for driving the carriage in the main scanning direction;
A platen provided opposite to the main scanning direction of the carriage, and a paper feeding unit that feeds a print medium between the carriage and the platen;
A gap switching unit for adjusting a gap between the recording head and the print medium;
A print control unit that controls driving of the carriage drive unit, the paper feed unit, and the gap switching unit,
The printing control unit controls the driving of the carriage driving unit according to the thickness of the printing medium fed from the paper feeding unit during printing on the printing medium, and the carriage controls the carriage of the printing medium. A liquid discharge unit that moves to a carriage rising position or carriage lowering position provided outside.   2. The liquid ejection unit according to claim 1, wherein the carriage raising position is provided on one side of the feeding path of the printing medium, and the carriage lowering position is provided on the other side of the feeding path of the printing medium. .   When the thick paper is fed from the paper feeding unit, the print control unit controls the driving of the carriage driving unit to move the carriage to the carriage raised position, and the gap switching unit and the recording head 3. The feed of the print medium is started by controlling the drive of the paper feed unit after increasing the gap between the print medium and the print medium. 4. The liquid discharge unit described in 1.   The printing control unit controls driving of the paper feeding unit when the thick paper is fed from the paper feeding unit, and feeds the printing medium to a position immediately before the movable range of the recording head. After controlling the drive of the carriage drive unit to move the carriage to the carriage lift position and increasing the gap between the recording head and the print medium by the gap switching unit, 3. The liquid ejection unit according to claim 1, wherein driving is controlled to feed the print medium between the carriage and the platen. 4.   When the thick paper is fed from the paper feed unit, the print control unit controls the drive of the paper feed unit to feed the print medium to a position immediately before the movable range of the recording head. After controlling the drive of the carriage drive unit to move the carriage to the carriage lift position and increasing the gap between the recording head and the print medium by the gap switching unit, 3. The liquid ejection unit according to claim 1, wherein driving is controlled to feed the print medium between the carriage and the platen. 4.   The printing control unit controls the driving of the carriage driving unit to control the driving of the carriage driving unit to print on the printing medium from the carriage rising position side when the carriage is moved to the carriage rising position. When the carriage is moved to the carriage lowering position by controlling the driving of the carriage driving unit, the driving of the carriage driving unit is controlled to start printing on the print medium from the carriage lowering position side. The liquid discharge unit according to claim 1, wherein the liquid discharge unit is a liquid discharge unit.   An apparatus for discharging a liquid, comprising the liquid discharge unit according to claim 1. A carriage provided with a recording head, a carriage drive unit that drives the carriage in the main scanning direction, and a platen that is disposed opposite the main scanning direction of the carriage, and feeds a print medium between the carriage and the platen A paper feed unit, a gap switching unit that adjusts a gap between the recording head and the print medium, a print control unit that controls driving of the carriage drive unit, the paper feed unit, and the gap switch unit, Using a liquid discharge unit equipped with
When printing on the print medium, the carriage driving unit is controlled according to the thickness of the print medium fed from the paper feed unit, and the carriage is provided outside the print medium feed path. An image forming control method, wherein the image forming control method moves to a raised position or a carriage lowered position.